| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | COVER ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
||||||||
|
||||||||||
Ms. Doyle is Director, Nutrition and Physical Activity, American Cancer Society, Atlanta, GA.
Dr. Kushi is Associate Director for Etiology and Prevention Research, Kaiser Permanente, Oakland, CA.
Dr. Byers is Professor, Department of Preventive Medicine and Biometrics; and Deputy Director, University of Colorado Cancer Center, Aurora, CO.
Dr. Courneya is Professor and Canada Research Chair in Physical Activity and Cancer, Faculty of Physical Education, University of Alberta, Edmonton, Alberta.
Dr. Demark-Wahnefried is Professor, School of Nursing and Department of Surgery, Duke University Medical Center, Durham, NC.
Ms. Grant is Oncology Nutritionist, Saint Alphonsus Regional Medical Center, Cancer Care Center, Boise, ID.
Dr. McTiernan is Full Member, Fred Hutchinson Cancer Research Center, Cancer Prevention Research Program, Seattle, WA.
Dr. Rock is Professor, Department of Family and Preventive Medicine, School of Medicine, University of California, San Diego, La Jolla, CA.
Dr. Thompson is Assistant Professor, University of Arizona Department of Nutritional Sciences, Tucson, AZ.
Dr. Gansler is Director of Medical Content, Health Promotions, American Cancer Society, Atlanta, GA.
Ms. Andrews is Research Associate, Cancer Control Science, American Cancer Society, Atlanta, GA.
This article is available online at http://CAonline.AmCancerSoc.org
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONOVERVIEW OF THE REPORTNUTRITION AND PHYSICAL ACTIVITY...CANCER AND CANCER TREATMENTSELECTED ISSUES IN NUTRITION...NUTRITION AND PHYSICAL ACTIVITY...COMMON QUESTIONS ABOUT DIET,...ACS 2006 NUTRITION, PHYSICAL...REFERENCES |
|---|
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONOVERVIEW OF THE REPORTNUTRITION AND PHYSICAL ACTIVITY...CANCER AND CANCER TREATMENTSELECTED ISSUES IN NUTRITION...NUTRITION AND PHYSICAL ACTIVITY...COMMON QUESTIONS ABOUT DIET,...ACS 2006 NUTRITION, PHYSICAL...REFERENCES |
|---|
Nutritional needs change for most persons during the phases of cancer survivorship. Although many cancer survivors live with active or advanced disease, a large and growing number live extended, cancer-free lives. Sixty-five percent of Americans diagnosed with cancer now live more than 5 years.1 The need for informed lifestyle choices for cancer survivors becomes particularly important as they look forward to successful completion of therapy and search for the best strategies to recover from treatment and improve their long-term outcomes. For long-term cancer survivors, an appropriate weight, a healthful diet, and a physically active lifestyle aimed at preventing recurrence, second primary cancers, and other chronic diseases should be a priority. For some, managing nutritional needs while living with advanced cancer becomes a particular challenge.
After receiving a diagnosis of cancer, survivors soon find there are few clear answers to even the simplest questions, such as Should I change what I eat? Should I exercise more? Should I lose weight? Should I take dietary supplements? Cancer survivors receive a wide range of advice from many sources about foods they should eat, foods they should avoid, how they should exercise, and what types of supplements or herbal remedies they should take. Unfortunately, this advice is often conflicting.
|
OVERVIEW OF THE REPORT |
|---|
|
TOPABSTRACTINTRODUCTIONOVERVIEW OF THE REPORTNUTRITION AND PHYSICAL ACTIVITY...CANCER AND CANCER TREATMENTSELECTED ISSUES IN NUTRITION...NUTRITION AND PHYSICAL ACTIVITY...COMMON QUESTIONS ABOUT DIET,...ACS 2006 NUTRITION, PHYSICAL...REFERENCES |
|---|
This report presents information in four sections. The first section addresses nutrition and physical activity issues across the phases of cancer survivorship, including treatment, recovery, living after recovery from treatment, and living with advanced cancer. The second section discusses selected nutrition and physical activity issues, including body weight, food choices, alcohol, food safety, and physical activity. The third section provides information regarding selected cancer sites (breast, colorectal, hematological, lung, prostate, head and neck, and upper gastrointestinal). The fourth section includes common questions about diet, physical activity, and cancer survivorship.
It is important for both health care providers and cancer survivors to consider the nutritional and physical activity issues discussed in this report within the context of the individual survivor's overall medical and health situation. This report is not intended to imply that nutrition and physical activity are more important than other clinical or self-care approaches. For example, although we present nutritional suggestions for persons with nausea or fatigue, we recognize that other medical interventions may be more important in controlling these symptoms. In writing these suggestions, we have assumed that survivors are receiving appropriate medical and supportive care and are seeking information on self-care strategies to provide further relief of symptoms and to enhance health and improve the quality of their lives.
|
NUTRITION AND PHYSICAL ACTIVITY ACROSS THE CONTINUUM OF CANCER SURVIVORSHIP |
|---|
|
TOPABSTRACTINTRODUCTIONOVERVIEW OF THE REPORTNUTRITION AND PHYSICAL ACTIVITY...CANCER AND CANCER TREATMENTSELECTED ISSUES IN NUTRITION...NUTRITION AND PHYSICAL ACTIVITY...COMMON QUESTIONS ABOUT DIET,...ACS 2006 NUTRITION, PHYSICAL...REFERENCES |
|---|
|
CANCER AND CANCER TREATMENT |
|---|
|
TOPABSTRACTINTRODUCTIONOVERVIEW OF THE REPORTNUTRITION AND PHYSICAL ACTIVITY...CANCER AND CANCER TREATMENTSELECTED ISSUES IN NUTRITION...NUTRITION AND PHYSICAL ACTIVITY...COMMON QUESTIONS ABOUT DIET,...ACS 2006 NUTRITION, PHYSICAL...REFERENCES |
|---|
All of the major modalities of cancer treatment, including surgery, radiation, and chemotherapy, can significantly impact nutritional needs, alter regular eating habits, and adversely affect how the body digests, absorbs, and uses food.4,11 Commonly experienced symptoms of cancer and side effects of treatment that may impact nutritional status include changes in taste or smell, loss of appetite, nausea, vomiting, changes in bowel habits, weight change, loss of lean mass and sarcopenia, pain, and fatigue.12–14 If these occur, usual food choices and eating patterns may need to be temporarily adjusted to optimize intake and meet nutritional needs.
During active cancer treatment, the overall goals of nutritional care for survivors should be to prevent or reverse nutrient deficiencies, to preserve lean body mass, to minimize nutrition-related side effects (such as decreased appetite, nausea, taste changes, or bowel changes), and to maximize quality of life. Recent studies confirm the benefit of dietary counseling during cancer treatment for improving outcomes, such as fewer treatment-related symptoms, improved quality of life, and better dietary intake.15–18 Suggestions for finding an oncology nutrition expert to provide dietary counseling are provided in Table 1. Providing short-term individualized nutritional support can improve appetite and dietary intake and decrease the toxicities associated with cancer treatments.4 Examples of individualized nutritional therapies include the following:
|
Given this uncertainty, until more evidence is available that suggests more benefit than harm, it is prudent for cancer survivors receiving chemotherapy or radiation therapy to avoid exceeding more than 100% of the daily value for antioxidant-type vitamins such as vitamins C and E during the treatment phase.19–22
Exercise During Cancer Treatment
An increasing number of studies have examined the therapeutic value of exercise during primary cancer treatment.30–32 Most of these studies have examined women with early-stage breast cancer receiving adjuvant therapies (eg, chemotherapy, radiotherapy) and persons with various cancers immediately after bone marrow transplantation. Despite methodologic limitations and small sample sizes, existing evidence strongly suggests that exercise is not only safe and feasible during cancer treatment, but that it can also improve physical functioning and some aspects of quality of life.30–33 It is unknown if exercise has any effects on cancer treatment completion rates or on the efficacy of cancer treatments. However, one animal study reported that exercise did not interfere with the efficacy of chemotherapy.34 Although there is not a strong biological rationale for concerns about adverse effects of exercise during treatment, research into this question is needed.
The decision regarding how to maintain or when to initiate physical activity should be individualized to the survivor's condition and personal preferences. In some circumstances, a training program to improve cardiopulmonary fitness before cancer treatments might aid recovery, although adequate research has not been done in this area. Cross sectional research among men who received radiation therapy for prostate cancer, however, suggests that men who exercise routinely have significantly decreased risk of erectile dysfunction post-treatment.35 Likewise, resistance training programs may be helpful in hindering rapidly occurring adverse body composition changes (ie, sarcopenic obesity and osteopenia) that may occur among some cancer patients who receive systemic therapy.36 Persons receiving chemotherapy and radiation therapy who are already on an exercise program may need temporarily to exercise at a lower intensity and progress at a slower pace, but the principal goal should be to maintain activity as much as possible. For those who were sedentary before diagnosis, low-intensity activities such as stretching and brief, slow walks should be adopted and slowly advanced. For older persons and those with bone disease or significant impairments such as arthritis or peripheral neuropathy, careful attention should be given to balance and safety to reduce the risk for falls and injuries. The presence of a caregiver or exercise professional during exercise sessions can be helpful. If the disease or treatment necessitates periods of bed rest, then reduced fitness and strength, as well as loss of lean body mass, can be expected. Physical therapy during bed rest is therefore advisable to maintain strength and range of motion and to help to counteract the fatigue and depression that are often experienced under those circumstances. Some clinicians advise some survivors to wait to determine their physical response to chemotherapy before beginning an exercise program.
Recovery
After cancer therapy has been completed, the next phase of cancer survival is recovery. In this phase, many survivors' symptoms and side effects of treatment that impact nutritional and physical well-being begin to diminish and resolve. Typically, survivors recover from the acute effects of their specific treatment within a few weeks after completing therapy, though in some instances, toxic effects of treatment may persist. In addition, late-occurring effects of treatment may appear long after treatment has been completed.37,38 Examples of continuing side effects or complications of cancer treatment relevant to nutritional status include persistent anorexia, changed sense of taste, inability to replenish lean body mass after completion of therapy, and persistent diarrhea or constipation.
Survivors require ongoing nutritional assessment and guidance in this phase of survival.13,14,39 For those who emerge from treatment underweight or who have compromised nutritional status, continued supportive care, including dietary counseling and pharmacotherapy (eg, drugs to relieve symptoms and stimulate appetite), is helpful in the recovery process.15,40 After treatment, a program of regular physical activity is essential to aid in the process of recovery and improve fitness.
Living After Recovery
During this phase, setting and achieving lifelong goals for an appropriate weight, a physically active lifestyle, and a healthy diet are important to promote overall health, quality of life, and longevity.41 The ACS has established nutrition and physical activity guidelines for the prevention of cancer (Table 2).42 Although it may seem reasonable to assume that following these guidelines would also favorably affect cancer recurrence or survival rates, few data are available to directly support this assumption. In some instances, there is evidence for such a link, as with obesity and breast cancer recurrence, but in many instances the evidence linking food choices and physical activity to cancer recurrence and survival is limited or unclear. Although the scientific evidence for advice on nutrition and physical activity after cancer is much less certain than for cancer prevention, it is likely that following the ACS Guidelines on diet, nutrition, and cancer prevention may be helpful for reducing the risk of developing second cancers.42 It is also important to realize that, because persons who have been diagnosed with cancer may be at increased risk for other cancers and for cardiovascular disease, diabetes, and osteoporosis, the guidelines established to prevent those diseases are especially important for cancer survivors.43–48
|
An increasing number of studies have examined exercise during recovery and long-term survival after cancer treatment.30–32 Most research has been conducted among women with breast cancer or those who have received bone marrow transplants. Exercise has been shown to improve cardiovascular fitness, muscle strength, body composition, fatigue, anxiety, depression, self-esteem, happiness, and several components of quality of life (physical, functional, and emotional) in cancer survivors.30 A few recent cohort studies have examined the association between physical activity and cancer recurrence, cancer-specific mortality, and all-cause mortality in cancer survivors.52–55 Data from almost 3,000 breast cancer survivors in the Nurses' Health Study showed that higher levels of post-treatment physical activity were associated with a 26% to 40% reduction in the risk of breast cancer recurrence, breast cancer-specific mortality, and all-cause mortality. The risk reduction was seen with as little as 1 to 3 hours per week of moderate intensity activity with further reductions for those performing 3 to 5 hours per week.55 Similar associations have been reported between physical activity and clinical outcomes in colorectal cancer survivors.52–54 Although preliminary, these data suggest that physical activity may be important for reducing the risk of recurrence and extending survival for some cancer survivors.
Living With Advanced Cancer
Although some persons are cured or experience cancer as a controllable chronic disease, others live with advanced cancer. For these persons, a healthy diet and physical activity are important factors in establishing and maintaining a sense of well-being and enhancing quality of life. Although advanced cancer may be accompanied by substantial weight loss, it is not inevitable that persons with cancer lose weight or experience malnutrition.4 Many persons with advanced cancer may need to adapt food choices and eating patterns to meet nutritional needs and to manage symptoms and adverse effects such as pain, constipation, and loss of appetite. For persons with poor appetite, weight loss, or both, convincing evidence exists that some medications (eg, megestrol acetate) enhance appetite.56–59 Furthermore, using nonsteroidal anti-inflammatory drugs or omega-3 fatty acid oral supplements may stabilize or improve nutritional status, body weight, and functional status.60–63
Additional nutritional support such as nutrient-dense beverages can be provided for those who cannot eat enough solid food to maintain energy intake. The use of tube feedings and total parenteral nutrition should be individualized with clear recognition of the associated risks for complications. Both the American Society for Parenteral and Enteral Nutrition and the American Dietetic Association recommend that total parenteral nutrition should be used selectively and with caution.64,65
In principle, some level of physical activity is desirable for persons with advanced cancer, but there is limited research on exercise in such individuals. Thus, the evidence of benefit from exercise for advanced cancer survivors is insufficient to make specific recommendations. Recommendations for nutrition and physical activity for persons who are living with advanced cancer are best made based on individual needs and abilities.
|
SELECTED ISSUES IN NUTRITION AND PHYSICAL ACTIVITY FOR CANCER SURVIVORS |
|---|
|
TOPABSTRACTINTRODUCTIONOVERVIEW OF THE REPORTNUTRITION AND PHYSICAL ACTIVITY...CANCER AND CANCER TREATMENTSELECTED ISSUES IN NUTRITION...NUTRITION AND PHYSICAL ACTIVITY...COMMON QUESTIONS ABOUT DIET,...ACS 2006 NUTRITION, PHYSICAL...REFERENCES |
|---|
In the United States, obesity is a problem of epidemic proportions66 and is a well-established risk factor for some of the most common cancers.49 Increased body weight has been associated with increased risk for cancers at several specific sites, including the breast (postmenopausal), colorectum, esophagus, liver, gallbladder, pancreas, kidney, uterus, and for advanced prostate cancer.49,67–70 Thus, many cancer survivors are overweight or obese at the time of diagnosis. Increasing evidence indicates that being overweight increases the risk for recurrence and reduces the likelihood of survival for many cancers.10,50,68,71–74
For cancer survivors who are overweight or obese, modest weight loss (ie, a maximum of 2 pounds per week)75,76 can be encouraged during treatment, as long as the treating oncologists approve, weight loss is monitored closely, and weight loss does not interfere with treatment. Safe weight loss should be achieved through a well-balanced diet that is reduced in energy density and increased physical activity tailored to the specific needs of the person being treated. After cancer treatment, weight gain or loss should be managed with a combination of dietary and physical activity strategies. For some who need to gain weight, this means increasing energy intake (food intake) to exceed energy expended, and for others who need to lose weight, this means increasing energy expenditure (via increased physical activity) to exceed energy intake. Emerging evidence suggests that reducing the energy density of the diet by emphasizing low-energy density foods (eg, water- and fiber-rich vegetables, fruits, and soups; cooked whole grains) and limiting intake of fat and sugars promotes healthy weight control.77 The mechanism by which this strategy may be useful is that food volume is not reduced, which may help to avoid hunger and feelings of deprivation. Limiting portion sizes of energy dense foods is an important accompanying strategy.78–81 Increased physical activity is also an important element to prevent weight gain, promote weight loss, and most important, to promote maintenance of weight loss in patients who are overweight or obese.82 For those who need to lose weight, even if ideal weight reduction is not achieved, it is likely that any weight loss achieved by physical activity and healthful eating is beneficial, with weight losses of 5% to 10% still likely to have significant health benefits.43 Although the evidence related to these weight management strategies does not come from studies of cancer survivors, it is likely that these common-sense approaches can apply in the special circumstances of the cancer experience.
Nutrition and Food Choices
During all phases of cancer survival, even for those with no apparent nutritional problems, the principles outlined in the American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention should be regarded as the basis for a healthful diet.42 These guidelines are similar to those recommended by several other organizations, agencies, and expert panels as a reasonable basis for the dietary prevention of other chronic diseases and cancer.43,46,83
Balancing Fat, Protein, and Carbohydrate Intake
Protein, carbohydrate, and fat all contribute energy (calories) to the diet, and each of these dietary constituents is available from a wide variety of foods. Informed choices about foods that provide these macronutrients should be based in goals of achieving variety and nutrient adequacy. Many cancer survivors are at high risk for other chronic diseases, such as heart disease. Therefore, the recommended amounts and type of fat, protein, and carbohydrate to reduce cardiovascular disease risk are also appropriate for cancer survivors.42–46
Several studies have been conducted on the relationship between fat intake and survival after the diagnosis of breast cancer, and the results across these studies are inconsistent, with some studies suggesting increased fat intake may decrease survival, whereas others suggest no effect.84 Two large clinical trials, one recently completed and the other still ongoing, were designed to test whether a reduction in fat intake can reduce risk for recurrence and increase overall survival in women who have been diagnosed with early stage breast cancer (the Women's Intervention Nutrition Study [WINS] and the Women's Healthy Eating and Living [WHEL] Study).85,86 Preliminary results from the recently-completed WINS suggest that women assigned to the low-fat diet arm of the study (targeting 20% of energy from fat) exhibited a 24% reduction in risk for recurrence; subset analyses suggest that this effect was even greater among women with estrogen receptor-negative disease.87 Results from the WHEL Study are anticipated by 2008. A smaller number of observational follow-up studies of diet and survival after the diagnosis of prostate cancer have also been reported. In one of these studies, higher saturated fat intake predicted shorter disease-specific survival, and in another, greater monounsaturated fat intake predicted longer survival.88,89
Currently, the recommended level of fat in the diet is 20% to 35% of energy, with saturated fat intake limited to <10% and trans fatty acids limited to <3% of total energy intake.82 Some studies have suggested that omega-3 fatty acids may have specific benefits for cancer survivors, such as ameliorating cachexia, improving quality of life, and perhaps enhancing the effects of some forms of treatment.90,91 These findings are not certain, however, and more research is needed.92 However, including foods that are rich in omega-3 fatty acids (eg, fish, walnuts) in the diet should still be encouraged because this is associated with a lower risk for cardiovascular diseases and a lower overall mortality rate,43,45,46 and evidence is largely lacking for a detrimental effect.
Adequate protein intake is essential during all stages of cancer treatment, recovery, and long-term survival. The best choices to meet protein needs are foods that are also low in saturated fat (eg, fish, lean meat and poultry, eggs, nonfat and low-fat dairy products, nuts, seeds, and legumes). An intake of 10% to 35% of energy from protein, or at least 0.8 g/kg body weight, is recommended for the general population82 and will generally meet the protein needs of adult cancer survivors.
Healthful carbohydrate sources are foods that are rich in essential nutrients, phytochemicals, and fiber, such as vegetables, fruit, whole grains, and legumes. These foods should provide the majority of carbohydrate in the diet. The recommended level of carbohydrate in the diet is 45% to 65% of energy intake for the general population.82 Vegetables and fruits contain numerous dietary constituents that potentially affect cancer progression, such as essential vitamins and minerals, biologically active phytochemicals, and fiber. Additionally, these are low energy dense foods that promote satiety, and thus may promote healthy weight management.93 Whole fruit (instead of juice) adds more fiber and fewer calories to the diet. When fruit juice is chosen, 100% fruit juice is the preferred choice.
Whole grains are rich in a variety of compounds (in addition to fiber) that have important biologic activity, including hormonal and antioxidant effects. For example, whole grains contain antioxidants, such as phenolic acids, flavonoids, and tocopherols; compounds with weak hormonal effects such as lignans; and compounds that may influence lipid metabolism, such as phytosterols and unsaturated fatty acids. All of these compounds and their biologic effects have been hypothesized to reduce risk and progression of cancer as well as cardiovascular disease.94 Choosing whole grains and whole grain food products as a source of fiber, rather than relying on fiber supplements, adds nutritional value to the diet.
Refined grains have been milled, a process that removes the bran and germ. This results in levels of vitamins and minerals that are lower than the unrefined, whole grain counterpart. Examples of refined grain products include white flour, degermed cornmeal, white bread, and white rice. In the United States, most refined grain products have been enriched, which means that micronutrients such as thiamin, riboflavin, niacin, iron, and folate have been added back to the product after processing. Thus, they are not completely without nutritional value, but many of the potentially helpful constituents, such as fiber and other biologically active phytochemicals, have not been added back.
Sugar intake has not been shown to directly increase risk or progression of cancer. However, sugars (including honey, raw sugar, brown sugar, high-fructose corn syrup, and molasses) and beverages that are major sources of these sugars (such as soft drinks and many fruit-flavored drinks) add substantial amounts of calories to the diet and thus can promote weight gain. In addition, most foods that are high in sugar do not contribute many nutrients to the diet and often replace more nutritious food choices. Therefore, limiting sugar consumption is recommended.
Vegetarian diets can be healthy or unhealthy, depending on one's food choices. Vegetarian diets differ with respect to inclusion of dairy foods, fish, and/or eggs, but avoiding red meat is a universal feature. Fish, dairy foods, or both contain sufficient quantity and quality of protein, and a vegetarian diet that contains these foods typically has a nutrient content similar to an omnivorous diet. A vegan diet, which excludes all animal foods and animal products, can meet protein needs if nuts, seeds, legumes, and cereal-grain products are consumed in sufficient quantities, although supplemental vitamin B12 will be necessary to meet needs for that vitamin. As dietary vitamin D in the United States comes primarily from fortified dairy foods, a vegan diet may also need to include supplemental vitamin D if adequate exposure to the sun or ultraviolet light is not obtained. Vegetarian diets can have many healthful characteristics because they tend to be low in saturated fat and high in fiber, vitamins, and phytochemicals. A vegetarian diet is consistent with the ACS Nutrition Guidelines for the Prevention of Cancer. However, no direct evidence has determined whether consuming a vegetarian diet has any additional benefit for the prevention of cancer recurrence over an omnivorous diet high in vegetables, fruits, and whole grains, and low in red meats.
Vegetables and Fruits
Higher intakes of vegetables and fruits have been specifically associated with a lower incidence of cancer at several sites, including the colorectum, stomach, lung, oral cavity, and esophagus.44 Few studies exist, however, on the relationship between a diet including many vegetables and fruits and the risk for reducing cancer recurrence or increasing survival after cancer. In the observational studies that have examined the relationship between intakes of vegetables and fruit (or nutrients indicative of those foods) and risk for recurrence of breast cancer, the findings have been mixed,84 although plasma carotenoids (a marker of vegetable and fruit intake) have been associated with greater likelihood of recurrence-free survival in one study.95 In the single study that examined diet and survival after the diagnosis of ovarian cancer, higher intake of vegetables, especially cruciferous vegetables, was found to be associated with longer survival.96 A recent observational study of diet after diagnosis and risk of prostate cancer progression found those who consumed more tomato sauce had longer survival.97
The benefits of eating a variety of vegetables and fruits probably exceed the health-promoting effects of any individual constituents in these foods because the various vitamins, minerals, and other phytochemicals in these whole foods act in synergy. It is reasonable to recommend that cancer survivors adopt the general recommendations issued by the ACS for cancer prevention to eat at least five servings of a variety of vegetables and fruit each day. This can be achieved by eating a minimum of 2 1/2 cups of vegetables and fruits each day. Colorful choices such as dark green and orange vegetables are typically good sources of nutrients and healthful phytochemicals. Fresh, frozen, canned, raw, cooked, or dried vegetables and fruits all contribute nutrients and other biologically active constituents to the diet. Cooking vegetables and fruits, especially with methods such as microwaving or steaming in preference to boiling in large amounts of water, preserves the bioavailability of water-soluble nutrients and can improve absorption of others. For example, the antioxidant lycopene is better absorbed from cooked tomato and tomato products than from raw tomatoes. At present, no research exists to demonstrate that organically grown vegetables and fruits are superior in their content of potential cancer-preventive constituents.
Alcohol
Substantial observational evidence indicates that alcohol intake has both positive and negative health effects.44,98,99 Alcoholic drinks up to one or two drinks per day (for women and men, respectively) can lower risk for heart disease, but higher levels do not offer additional benefit and may increase risk not only for complications of alcohol overuse, but also for cancer. For this reason, it is important for the health care provider to tailor advice on alcohol consumption to the individual cancer survivor. The cancer type and stage of disease, treatment, risk factors for recurrence or new primary cancers, and comorbid conditions should be considered in making recommendations. For example, alcohol, even in the small amounts found in mouthwashes, can be irritating to survivors with oral mucositis and can exacerbate that condition. Therefore, it is reasonable to recommend that alcohol intake should be avoided or limited among survivors with mucositis and among those beginning head and neck radiotherapy or chemotherapeutic regimens that put them at risk for mucositis.
Many studies have found a link between alcohol intake and risk for some primary cancers, including cancers of the mouth, pharynx, larynx, esophagus, liver, breast, and probably colon cancer.44,98,100 In persons who have already received a diagnosis of cancer, alcohol intake could also affect the risk for new primary cancers of these sites. Alcohol intake can increase the circulating levels of estrogens, which theoretically could increase the risk for recurrence of breast cancer. In most studies of breast cancer survivors conducted to date, there is little evidence of an effect of alcohol on increased risk of recurrence or decreased survival.73 However, the level of alcohol intake in these studies of women with breast cancer has generally been so low that the results of these studies should not be interpreted as indicating alcohol intake after cancer diagnosis does not increase risk of recurrence or new primary cancers.101 Therefore, the degree of risk present should be considered in recommendations regarding individual alcohol consumption.
Food Safety
Food safety is of special concern for cancer survivors, especially during episodes of iatrogenic immunosuppression that can occur with certain cancer treatment regimens.102 Survivors can become susceptible to developing infections due to treatment-induced leukopenia and neutropenia. During any immunosuppressive cancer treatment, survivors should take extra precautions to prevent infection, and they should be particularly careful to avoid eating foods that may contain unsafe levels of pathogenic microorganisms. Because chemotherapy can impair the immune response, raw vegetables and fruits may increase the risk for infection in some patients during immune-suppressant treatment (ie, some chemotherapies and radiotherapies) as a result of bacteria on these foods.102 By following safe food practices, cancer survivors and their caregivers can reduce the risk of food-borne illness. Refer to the general guidelines for food safety as shown in Table 3.
|
The VITAL (Vitamins and Lifestyle) cancer patient cohort study provides estimates of the frequency with which cancer survivors use specific dietary supplements. Data collected from more than 10,800 cancer survivors showed significant differences across cancer sites, including the use of cranberry extract among patients with bladder cancer, folic acid supplementation among patients with colorectal and uterine cancer, and vitamin A supplementation among women diagnosed with ovarian cancer, as well as both men and women who had been diagnosed with melanoma. Interestingly, although there is little direct evidence of a beneficial effect of vitamin E in breast cancer survival, this study reported increased vitamin E use among breast cancer patients (49.2% of women previously diagnosed with breast cancer), a practice that was also reported by 46% of breast cancer survivors in another study.106 The quantity of vitamin E intake in this study also indicated that supplementation levels were much higher than for healthy adults (averaging 268 mg/d and 34 mg/d, respectively).
During and after cancer treatment, there is a probable benefit of taking a standard multiple vitamin and mineral supplement that contains approximately 100% of the Daily Value because during these times, it may be difficult to eat a diet with adequate amounts of these micronutrients.110,111 One report among children with cancer showed that diets were inadequate in vitamin C and E and total carotenoids. In this same study, diets with sufficient vitamin E were associated with lower risk for infection, and diets adequate in vitamin C were associated with fewer delays in treatment related to low blood counts,112 suggesting that working to improve dietary adequacy through food selections may improve health during treatment for cancer. In contrast, the use of very large doses of vitamins, minerals, and other dietary supplements is not recommended.113,114 There is reason for caution in taking high-dose supplements. The best example of this risk comes from studies of beta-carotene and lung cancer. Although many observational epidemiologic studies suggested that dietary beta-carotene was associated with lower risk for lung cancer,115 two clinical trials showed that high-dose beta-carotene supplements actually increased (not decreased) the rate of occurrence of lung cancer.113,114 In addition, one recent trial suggests that beta-carotene supplements may increase colorectal adenoma recurrence in persons who smoke cigarettes, consume alcohol, or both.116 High doses of beta-carotene taken as a supplement clearly do not result in the same effects as consumption of dietary patterns that include foods rich in beta-carotene. Because other vitamins and micronutrients at high doses have not been studied in large clinical trials, the adverse effects of high-dose beta-carotene should suggest caution in the use of high-dose nutritional supplements. There are, however, some indications for lower-dose nutrient supplementation by cancer patients and survivors. These include the following:
Open dialogue between patients and health care providers should occur regarding dietary supplementation to assure there is no contraindication in relation to the prescribed cancer therapy or for longer-term health effects.117,118 In turn, health care providers should make an effort not only to provide time to review dietary supplement decisions with patients, but also to stay abreast of recent research in this area, particularly related to potential drug interactions. It is most prudent to encourage cancer survivors to obtain the potentially beneficial compounds from food. A daily multivitamin supplement in amounts equivalent to 100% of the Daily Value is a good choice for anyone who, for whatever reasons, cannot eat a healthful diet,110,111 but the need for vitamin and mineral supplements in higher doses should be assessed and discussed on an individual basis.
Physical Activity Issues for Cancer Survivors
Physical activity may have benefits throughout the spectrum of the cancer experience, but cancer survivors are often more likely to become sedentary for several reasons. Survivors tend to decrease their physical activity levels after their diagnosis of cancer, and most continue lower levels of activity through treatment and beyond, rarely returning to their prediagnosis levels of activity.119–121 Because being sedentary is a risk factor for the incidence of several of the most common types of cancer, such as breast cancer and colorectal cancer, many survivors from these cancers will tend to have been sedentary before diagnosis. In addition, some therapies may reduce the capacity to exercise because of adverse effects on cardiopulmonary, neurologic, and muscular systems. Thus, both preexisting reduced levels of fitness, stamina, and strength and the new stresses of cancer diagnosis, treatment, and recovery challenge cancer survivors who want to increase their physical activity levels. For these reasons, exercise that is of low or moderate intensity for a healthy person may seem to be of high intensity for some cancer survivors.
Physical activity capabilities and effects will differ among cancer survivors depending on their diagnosis, treatment modalities, and the spectrum of cancer survival.122 Many cancer survivors are at increased risk for comorbid conditions that can be reduced through increased physical activity.123 The effects of physical activity on cardiovascular disease and diabetes have not been studied in cancer survivors, but it is reasonable to expect that the beneficial effects of physical activity on such outcomes would not differ from those observed in the general population. Similarly, resistance exercise has been reported to improve bone strength in persons without cancer; thus, resistance exercise programs may be expected to favorably decrease risk of osteoporosis in cancer survivors, although such effects have not yet been studied. Women who experience menopause during or after treatment and men with prostate cancer who are treated with long-term androgen-suppressive medications are at high risk for osteoporosis124,125 and may therefore be especially likely to benefit from resistance training to increase bone strength. Additional positive outcomes of exercise training can include improved lean body mass and balance, with resulting reduced risk for falls and subsequent fractures. Clinical trials are underway that are testing the effects of aerobic and resistance exercise on bone density in postmenopausal breast cancer survivors.
Cancer survivors with lymphedema may also benefit from exercise, specifically range-of-motion exercises, with approval from their treating physicians. The benefits and risks of resistance training in survivors with lymphedema have not been investigated systematically. There have been some concerns that physical activity involving the affected limbs may have adverse effects on lymphedema. However, this is an area that is understudied, and the few results, including from a randomized trial, an early pilot clinical study, and a small cohort study, suggest that resistance training does not adversely affect lymphedema.126–128
No clinical trials have reported the effect of physical activity on the risk for cancer recurrence or survival, but several clinical trials have assessed the effect of physical activity interventions on quality of life and other psychosocial outcomes in cancer survivors. The exercise programs in these trials were primarily 3 days per week of moderate to vigorous activity that was progressively increased in duration to approximately 45-minute sessions during a period of 3 or 4 months. These studies have shown that such exercise programs can reduce anxiety and depression, improve mood, boost self-esteem, and reduce symptoms of fatigue.30 In general, physical activity is likely to be beneficial for most cancer survivors who have completed their primary treatments.
Although some cancer survivors can adopt an exercise program independently, many will benefit from referral to an exercise specialist. Survivors should seek individuals who have been certified by an exercise-related professional organization, such as the American College of Sports Medicine. A physical therapist is the appropriate resource for survivors with injuries, pain, or specific postsurgical issues such as lymphedema or amputation. Exercise physiologists receive college training and are certified by various professional organizations to develop individualized exercise programs. Personal trainers are also popular choices for persons who want to increase their fitness and activity levels. Recommendations on the type, frequency, duration, and intensity of exercise should be individualized to the survivor's age, previous fitness activities, type of cancer, stage of treatment, type of therapy, and comorbid conditions. Table 4 contains some suggested ways to increase physical activity.
|
For the general population, the ACS recommends at least 30 to 60 minutes of moderate to vigorous physical activity at least 5 days per week to reduce the risk for cancer, cardiovascular disease, and diabetes.42,46,123 These levels of activity have not been studied systematically in cancer survivors, but aside from specific circumstances related to treatment or other cancer-specific conditions such as outlined above, there is no reason to think that these recommendations would not also be beneficial for cancer survivors. Therefore, although daily and regular activity may be preferred and may be a goal, any steps that are taken to move from a sedentary to an active lifestyle should be encouraged. If an individual has been completely sedentary, encouragement to take short walks may be appropriate. If someone already exercises three times a week, encouragement to increase this to five times a week may be appropriate. For survivors wanting maximum benefit, the message should be that the health benefits of exercise are generally linear, with increasing health benefit with a higher volume of physical activity. Caution should be noted that extremely high levels of exercise might increase the risk for infections,129 and the risk of exercise-related injuries should also be minimized.
|
NUTRITION AND PHYSICAL ACTIVITY ISSUES BY SELECTED CANCER SITES |
|---|
|
TOPABSTRACTINTRODUCTIONOVERVIEW OF THE REPORTNUTRITION AND PHYSICAL ACTIVITY...CANCER AND CANCER TREATMENTSELECTED ISSUES IN NUTRITION...NUTRITION AND PHYSICAL ACTIVITY...COMMON QUESTIONS ABOUT DIET,...ACS 2006 NUTRITION, PHYSICAL...REFERENCES |
|---|
Several studies have examined exercise during and after treatment in breast cancer survivors.150,153 Few studies are large randomized clinical trials, but the evidence consistently suggests a benefit from exercise during and after breast cancer treatment on various measures of quality of life, as well as physical fitness (eg, cardiovascular endurance, flexibility, and body composition) and factors such as self-esteem, anxiety, depression, and fatigue.150 There are good reasons to suspect that the benefits of physical activity for the primary prevention of breast cancer, heart disease, diabetes, and overall mortality rate would also extend to breast cancer survivors.55 Furthermore, recent studies suggest that breast cancer survivors who are physically active have significantly lower rates of recurrence, as well as disease-specific and overall mortality, than those who are sedentary.55,133
Research is currently under way to evaluate various components of the prudent dietary pattern on cancer-specific outcomes, as well as overall health. To date, evidence that dietary fat intake could be associated with risk for recurrence or survival is not strongly or consistently supportive, especially when total energy intake and the degree of obesity are considered.154,155 Two large clinical trials, one recently completed and the other an ongoing study, were designed to test whether change in diet composition can reduce risk for recurrence and increase overall survival in women who have been diagnosed with breast cancer. The recently-completed WINS was a randomized multicenter clinical trial testing whether a reduction in fat intake as an adjuvant to standard breast cancer therapy can reduce disease recurrence and increase survival for women with localized breast cancer. This trial was conducted among 2,437 postmenopausal women with early stage breast cancer, with 975 women randomly assigned to the low-fat dietary intervention group. Unpublished results suggest that study participants in the low-fat diet arm of the study (targeting 20% of energy from fat) exhibited a 24% reduction in risk for recurrence, with a greater reduction in risk observed in the subgroup of women with estrogen receptor-negative cancer.87
Eating more vegetables is inconsistently related to reducing breast cancer risk, and the evidence that fruit intake is related to recurrence or survival is weak.156,157 In the ongoing WHEL Study, the major intervention is on increased vegetable and fruit intake, although the intervention group women are also encouraged to reduce fat and increase fiber intakes.158 Results from the WHEL Study are anticipated by 2008. In a recent cross-sectional study of women assigned to the control arm of the WHEL Study, higher levels of baseline serum carotenoid concentrations (a biologic marker of vegetable and fruit intake) were found to be associated with longer recurrence-free survival.95 Vegetables can reduce the total energy density in the diet, and both vegetables and fiber are associated with improved satiety. Recent data on breast cancer survivors participating in the Nurses' Health Study, who were followed for a mean period of nearly 10 years postdiagnosis, suggest that those who consume a prudent diet, with higher intakes of fruits, vegetables, and whole grains and lower intakes of sugars, refined grains, and animal products, may not have significantly lower rates of recurrence or cancer-specific mortality, although women who report this eating pattern have significantly lower rates of mortality from other diseases, when compared to those who eat typical western diets.159
Low folate intake (determined in large part by low dietary intakes of fruit, vegetables, legumes, and grains) has been hypothesized to be related to increased breast cancer risk.160–162 Folate might ameliorate the adverse effects of alcohol on breast cancer risk because some studies have shown that the increased risk associated with alcohol is more pronounced among women reporting lower intakes of folate.162–164 A specific relationship between folate intake and risk for recurrence or survival in women who have been diagnosed with breast cancer has not been observed in studies that have addressed that question.165
Although alcohol intake has been linked with an increase in the risk for primary breast cancer,100 there is limited evidence from studies of breast cancer survivors of a relationship with the risk for recurrence and survival.73,166 This is in part due to the fact that alcohol intake among women in these studies of breast cancer prognosis is generally at very low levels.101 Theoretically, however, alcohol intake could affect the risk for a second primary breast cancer, for which all breast cancer survivors are at increased risk. Alcohol is an unusual factor, however, because it presents both risks and benefits. In the general population, clear and consistent evidence links moderate alcohol intake (1–2 drinks per day) with a lower risk for cardiovascular disease.99 For breast cancer survivors, the decision to drink alcoholic beverages at moderate levels is complex because they must consider their levels of risk for both cardiovascular disease and recurrent breast cancer.
There is considerable public and scientific interest in the role of soy foods in the prevention of breast cancer, although evidence from human studies in support for such a role is limited.167–170 The interest in soy foods stems from the observation that they are consumed commonly in most Asian countries, where the rates of breast cancer are lower than in the United States and other western countries, and several epidemiologic studies in Asia or in Asian-American populations suggest that soy food intake may decrease the risk of breast cancer. Soy contains high levels of plant isoflavones that exert a variety of anticancer activities in laboratory studies.167 Perhaps because soy has the potential to produce both estrogenic and antiestrogenic effects, studies on soy and breast carcinogenesis have produced conflicting results.167–170 For the breast cancer survivor, current epidemiologic and laboratory evidence suggests there are unlikely to be harmful effects when soy is provided in the diet consistent with amounts in a typical Asian diet; whether such levels of soy intake may result in beneficial effects is also unclear.167 This amount would be provided by as many as three servings per day of soy foods, such as tofu and soy milk. However, because higher doses of soy may have estrogenic effects170 and because higher levels of estrogens clearly increase the risk for breast cancer progression,166 it is prudent for breast cancer survivors to avoid the high doses of soy and soy isoflavones that are provided by more concentrated sources such as soy powders and isoflavone supplements.
As we consider results from the WINS trial87 and await results of the WHEL Study,86 it is important to remember that nutrition and physical activity recommendations to reduce the risks for primary breast cancer and heart disease are especially important for breast cancer survivors.42,46,171,172 Diets should emphasize vegetables and fruits, low amounts of saturated fats, and sufficient dietary fiber. If soy foods are consumed, intakes should be kept in moderation, and concentrated sources of isoflavones should be avoided. Most importantly, breast cancer survivors should strive to achieve and maintain a healthy weight through appropriate diet and regular physical activity.84 In addition, regular physical activity should be maintained regardless of any weight concerns.
Colorectal Cancer
Many epidemiologic studies indicate that colorectal cancer risk is increased by diets high in red and processed meats and low in vegetables and fruits and by sedentary lifestyles and obesity. Excess alcohol consumption may also increase the risk for this cancer.173 Whether these or other dietary factors also influence prognosis of colorectal cancer is largely unknown. Only a few studies have tried to determine whether dietary factors influence prognosis after colorectal cancer diagnosis, and their findings have varied. Findings from two studies suggest that increased body weight is associated with shorter survival.72,174 Three additional studies suggest that higher levels of physical activity may be associated with better clinical outcomes in colorectal cancer survivors.52–54
Because colorectal cancers arise from adenomatous polyps, the prevention of polyp recurrence has been a focus of considerable clinical research. To date, trials have failed to show benefits in preventing new polyp growth during a 3- or 4-year period from antioxidant vitamins, fiber supplements, or modest dietary changes to increase fruit and vegetable intake.175 Calcium supplements, however, provided a modest benefit in preventing polyp recurrence.176 Clinical trials testing the effects of folate, vitamin D, and selenium are underway. After a diagnosis of colorectal cancer, the most important determinants of survival seem to be adherence to the full treatment regimen (especially if chemotherapy is recommended) and colonoscopic surveillance to identify new lesions.
Three studies have shown positive associations among exercise, physical fitness, and quality of life among colorectal cancer survivors.120,177,178 Two recent studies have shown a positive association between physical activity and survival in colorectal cancer survivors.53,54 Moreover, the evidence for a relation between physical activity and the primary prevention of colon cancer is convincing.49 Consequently, there is emerging evidence that physical activity may improve quality of life, reduce risk of recurrence, and extend survival after colorectal cancer.
Colorectal cancer survivors should be advised to maintain a healthy weight, eat a well-balanced diet consistent with guidelines for cancer and heart disease prevention, and participate in regular physical activity. Colorectal cancer survivors with chronic bowel problems or surgery that affects normal nutrient absorption should be referred to a registered dietitian to modify their diets to accommodate these changes and maintain optimal health.
Hematologic Cancers and Cancers Treated With Bone Marrow Transplantation or Hematopoietic Stem Cell Transplantation
A possible relationship between dietary factors and outcomes of hematologic cancers has been examined in only a few studies to date. Overweight or obesity seems to adversely affect prognosis for patients who receive hematopoietic stem cell transplantation, although the evidence is limited. In a study that focused on clinical data from patients who underwent autologous stem cell transplantation, obesity had significant adverse effects on treatment-related toxicity and mortality, overall survival, and disease-free survival.179
Preliminary research has examined the effects of exercise in survivors of hematologic cancers. Most of these studies have been conducted in the context of acute recovery from bone marrow or stem cell transplantation.180–184 Overall, these studies have reported some beneficial effects of exercise on functional capacity and aerobic fitness, muscular strength, fatigue, and psychosocial functioning and quality of life. More recently, several studies have examined hematologic cancer survivors outside the context of stem cell transplantation.
Observational studies have reported associations between exercise and quality of life in non-Hodgkin lymphoma185 and multiple myeloma186 survivors. One uncontrolled intervention trial found that chronically fatigued Hodgkin disease survivors reported reduced fatigue after 20 weeks of aerobic exercise.187 Another study of patients with various cancers (mostly non-Hodgkin lymphoma and breast cancer) treated with high-dose chemotherapy and stem cell transplantation showed that a 6-week program of daily walking improved both physical performance and fatigue.182
The conditioning regimen of intensive chemotherapy, often in conjunction with total body irradiation, is associated with several specific side effects that have significant adverse nutritional consequences, such as nausea, vomiting, diarrhea, oropharyngeal mucositis, and esophagitis. Total body irradiation damages the gastrointestinal mucosa, resulting in malabsorption and diarrhea because these epithelial cells are highly susceptible to the effects of radiation. Nutritional problems also result from adverse effects of various drug therapies, such as oral immunosuppressive agents and antibiotics that may be necessary for post-transplant management. Finally, the common complication of graft-versus-host disease (in patients who receive an allogeneic transplant) results in abdominal pain, nausea, severe diarrhea, malabsorption, and substantial nitrogen losses. Patients who do not receive nutrition support or specialized nutritional support typically eat poorly for a prolonged period and are at high risk of poor nutritional status.188–190
As an infection prevention strategy, low-microbial diets are often prescribed for transplant recipien
