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Cancer survivors are at increased risk for several comorbid conditions, and many seek lifestyle change to reduce dysfunction and improve long-term health. To better understand the impact of cancer on adult survivors' health and health behaviors, a review was conducted to determine (1) prevalent physical health conditions, (2) persistent lifestyle changes, and (3) outcomes of previous lifestyle interventions aimed at improving health within this population.
Relevant studies from 1966 and beyond were identified through MEDLINE and PubMed searches.
Cancer survivors are at increased risk for progressive disease but also for second primaries, osteoporosis, obesity, cardiovascular disease, diabetes, and functional decline. To improve overall health, survivors frequently initiate diet, exercise, and other lifestyle changes after diagnosis. However, those who are male, older, and less educated are less likely to adopt these changes. There also is selective uptake of messages, as evidenced by findings that only 25% to 42% of survivors consume adequate amounts of fruits and vegetables, and approximately 70% of breast and prostate cancer survivors are overweight or obese. Several behavioral interventions show promise for improving survivors' health-related outcomes. Oncologists can play a pivotal role in health promotion, yet only 20% provide such guidance.
With 64% of cancer patients surviving > 5 years beyond diagnosis, oncologists are challenged to expand their focus from acute care to managing the long-term health consequences of cancer. Although more research is needed, opportunities exist for oncologists to promote lifestyle changes that may improve the length and quality of life of their patients.
Cancer survival has risen steadily over the past three decades for all cancers combined. Prevalence proportions estimated from cancer incidence and follow-up data from the Surveillance, Epidemiology, and End Results registry indicate that there currently are 9.8 million cancer survivors in the United States alone, representing between 3% and 4% of the entire US population.1-4 As advances in cancer detection, treatment, and care diffuse into clinical practice, the number of survivors is expected to increase. The aging of the population and a longer life expectancy in general will contribute further to this trend.
The proportion of long-term cancer survivors also continues to grow. Today, in the absence of other competing causes of death, an estimated 64% of those diagnosed with cancer can expect to be alive in 5 years, whereas in 1971 long-term survival was estimated at < 50%.4 As the number of survivors and their length of survival expand, long-term health issues specific to cancer survival are fast emerging as a public health concern. The purpose of this review is to (1) describe common medical sequelae occurring among adult cancer survivors, (2) summarize lifestyle changes that are pursued by this population after diagnosis, and (3) examine lifestyle interventions that may hold promise in reducing adverse treatment-related effects and comorbidity. Relevant observation and intervention studies were identified through MEDLINE and PubMed searches using the specific search term “cancer survivor,” as well as cross-referenced medical subject heading terms “neoplasms,” “survivors,” “diet,” “exercise,” “physical activity,” “smoking,” “intervention,” and “lifestyle.” Although all articles from 1966 and beyond were considered, for the sake of brevity the search was limited to articles in the English language that describe physical health outcomes and not inclusive of alternative or complementary medicine. Additionally, we incorporated summaries of recent reviews when they were available. Data suggest that although the cancer survivor is at risk for a host of conditions that range from cardiac compromise to secondary cancers, the oncologist may be optimally positioned to capitalize on the “teachable moment” created by the cancer diagnosis and play a pivotal role in guiding survivors toward behaviors that improve overall health and physical well-being.5-8
Cancer survivors are high healthcare utilizers who have several distinct healthcare issues.9 Data clearly show that cancer survivors are at greater risk for developing secondary cancers and other diseases; these risks may be brought on by cancer treatment, genetic predisposition, and/or common lifestyle factors.2,10-13 Although the threat of progressive or recurrent disease is at the forefront of health concerns for a cancer survivor, a comparison by Brown et al10 of > 1.2 million patient records obtained from the Surveillance, Epidemiology, and End Results database with those obtained from the National Center for Health Statistics shows that “the evidence that cancer patients die of noncancer causes at a higher rate than persons in the general population is overwhelming.” Increased morbidity and decreased functional status and disability that result from cancer, its treatment, or health-related sequelae also are significant concerns.
Second cancers account for a large number of new cancers.1,2,11,13 A second primary may result from host susceptibility (genetic predisposition or immunodeficiency), a clustering of risk factors, common carcinogenic influences, treatment for the first tumor (eg, breast cancer after treatment for Hodgkin's disease), diagnostic surveillance, a chance event, or the interaction of these factors.1,2,13 Second cancers may occur in the same organ site (eg, breast or colorectal) and also at other sites, with leukemia and solid tumors of the breast, bone, thyroid, and bladder being reported most frequently. Thus, survivors can benefit from guidelines established for the primary prevention of these secondary cancers, as well as continued surveillance.1,14,15
Obesity is a well-established risk factor for cancers of the breast (postmenopausal), colon, kidney (renal cell), esophagus (adenocarcinoma), and endometrium; thus, a large proportion of cancer patients are overweight or obese at the time of diagnosis.16,17 Additional weight gain also can occur during or after active cancer treatment, an occurrence that has been documented frequently among individuals with breast cancer but recently was reported among testicular and gastrointestinal cancer patients, as well.15,18,19 Given data that obesity is associated with cancer recurrence in both breast and prostate cancer and reduced quality of life (QOL) among survivors, there is compelling evidence to support weight-control efforts in this population.14,15,18-20 Also, gradual weight loss has proven benefits in controlling hypertension, hyperinsulinemia, pain, dyslipidemia, and improving levels of physical functioning—conditions that reportedly are significant problems in the survivor population.14,15,21 Accordingly, the American Cancer Society Recommendations for Cancer Survivors list the “achievement of a healthy weight” as a primary goal.14
Obesity represents one of several metabolic disorders that are frequently manifest among cancer survivors—disorders that are grouped under the umbrella of “the metabolic syndrome” and include diabetes and cardiovascular disease (CVD).14,19,21 Insulin resistance is the underlying event associated with the metabolic syndrome, and insulin resistance, co-occurring hyperinsulinemia, and/or diabetes have been reported as health concerns among cancer survivors.10,22-24 As Brown et al10 observed, diabetes may play a significant role in the increased number of non–cancer-related deaths among survivors; however, its role in progressive cancer is still speculative.16
Although there is one study that suggests that older breast cancer patients derive a cardioprotective benefit from their diagnosis and/or associated treatments (most likely tamoxifen),25 most reports indicate that CVD is a major health issue among survivors, as evidenced by mortality data that show that half of non–cancer-related deaths are attributed to CVD.10 Risk is especially high among men with prostate cancer who receive hormone-ablation therapy, patients who receive adriamycin, and patients who receive radiation treatment to fields surrounding the heart.10,11,22,26 Although more research is needed to explore the potential benefits of lifestyle interventions specifically within survivor populations, the promotion of a healthy weight through a low-saturated-fat diet with ample amounts of fruits and vegetables and moderate levels of physical activity is recommended.14,15
Osteoporosis and osteopenia are prevalent conditions in the general population, especially among women. Despite epidemiologic findings that increased bone density and low fracture risk are associated with increased risk for breast cancer,27-35 clinical studies suggest that osteoporosis is still a prevalent health problem among survivors.36-39 Data of Twiss et al37 indicate that 80% of older breast cancer patients have t scores less than −1 and thus have clinically confirmed osteopenia at the time of their initial appointment. Other cancer populations, such as premenopausal breast and prostate cancer patients, may possess good skeletal integrity at the onset of their disease but are at risk of developing osteopenia, which may ensue with treatment-induced ovarian failure or androgen ablation.38,39
Previous studies indicate that functional status is lowest immediately after treatment and tends to improve over time; however, the presence of pain and co-occurring diseases may affect this relationship.40 In the older cancer survivor, regardless of duration after diagnosis, the presence of comorbidity rather than the history of cancer per se correlates with impaired functional status.41 Cancer survivors have an almost two-fold increase in having at least one functional limitation; however, in the presence of another comorbid condition, the odds ratio increases to 5.06 (95% CI, 4.47 to 5.72).42 These findings have been confirmed by other studies in diverse populations of cancer survivors.43-46 A cost analysis by Chirikos et al45 indicates that “the economic consequence of functional impairment exacts an enormous toll each year on cancer survivors, their families and the American economy at large.”
There are a variety of behavioral interventions that may mitigate elevated risk for the host of conditions for which the cancer survivor is especially vulnerable.1,2,47 However, because research on cancer survivorship is only just now receiving the attention it deserves, few studies have quantified longer-term physiologic outcomes of lifestyle change specifically within this population.48,49 According to the 2003 American Cancer Society Guide for Informed Choices, Nutrition and Physical Activity During and After Cancer Treatment, although no consensus exists to support “convincing evidence of benefit” as it relates to either disease-free or overall survival, current data do provide support for “probable” and “possible” benefit for several health behaviors, such as striving for a healthy weight, eating more fruits and vegetables and less saturated fat, and increasing physical activity.14 Although the focus of this article is on physical health, it is worth mentioning that some health behaviors, such as exercise are consistently associated with positive effects on psychological or emotional well-being (eg, mood states, self-esteem, and QOL) and reductions in fatigue.50-53 A recent study by Blanchard et al54 of 326 survivors of breast, prostate, and colorectal cancer suggests that survivors who exercise regularly, as well as those who practice more than one healthful behavior (ie, routine exercise, consumption of 5+ servings of fruits and vegetables per day, and tobacco abstinence), have significantly higher levels of health-related QOL than those who do not adhere to behavioral guidelines. Similarly, McBride et al55 found that psychological distress was lower among 988 breast and prostate cancer survivors who practiced healthful behaviors compared to those who did not.
A substantial number of reports suggest that cancer survivors spontaneously adopt lifestyle changes in hopes of achieving improved health. To date, published findings exist on > 20 studies that have explored persistent lifestyle practices among cancer survivors that extend beyond the year after diagnosis (Table 1).54,56-80 Although the preponderance of data suggest that the practice of healthful behaviors is notably higher among survivors, caution exists; given that such findings may be subject to bias (ie, survivors who do respond may be more likely to practice healthful behaviors).54 Findings of a recent prospective study by Satia et al81 on a population-based sample (N = 737), however, suggest that changes in lifestyle do accompany the cancer diagnosis; they observed significant increases in vegetable intake (P = .002) and physical activity (P < .001) among 278 colorectal cancer survivors from prediagnosis to 2-year follow-up, as compared with no change in age-, race-, and sex-matched controls.
At the time of diagnosis, the incidence of smoking among cancer patients varies tremendously, with rates approaching 100% among those with tobacco-related cancers of the lung or esophagus2,60,65,66,71 and rates of < 10% among men and women diagnosed with non–tobacco-related cancers such as carcinoma of the prostate or breast.54,59 Quit rates vary accordingly and range from 46% to 96% among smokers with lung, head, or neck cancers, as compared with only 4% noted among smokers with breast cancer.59,60,61,65,66,72 Data from the National Health Interview Survey suggest that approximately 20% of cancer survivors continue to smoke. Although smoking prevalence among survivors is lower than that for those without a cancer history (24%), it is not appreciably lower. Also worrisome is the observation that the highest rates are among the youngest group of survivors (ages 18-44), > 40% of whom report current smoking.2 Alcohol abstinence ranges from 47% to 59% in those with head and neck cancers (in which the association between drinking and cancer is strong) to between 8% and 16% in breast and lung cancer survivors (in which the strength of association is either weaker and/or newly established).61,63,70 Current studies on alcohol and tobacco use among survivors are limited by their relatively short-term follow-up, especially given the history of recidivism for these addictive behaviors. To date, only Gritz et al65 have reported data on longer-term follow-up (up to 4 years postdiagnosis), showing durable quit rates of approximately 40% among smokers diagnosed with lung cancer.
Dietary modification is another prevalent behavior change noted after diagnosis. Consumption of a “healthier diet” is reported by 30% to 60% of survivors, with a majority indicating reduced intakes of meat and increased consumption of fruits and vegetables, although not all of these studies used standardized, validated instruments or subscales to ascertain dietary data. 58,59,64,68,69,70,73,74,76-78 A cross-sectional study by Tangney et al78 of 117 breast cancer survivors using a validated food-frequency questionnaire indicated mean Healthy Eating Index scores of 67.2 ± 13.2 within this population when compared with contemporaneous normative data existing on healthy women from the Continuing Survey of Food Intakes by Individuals (63.4 ± 13.3).82 The higher diet-quality scores described in this study were primarily a function of reported lower energy intakes (approximately 200 calories less per day) with concurrently higher fruit and lower meat consumption. Other studies suggest that 45% to 69% of survivors consume diets with < 30% of energy from fat and that 25% to 42% consume at least five servings of fruits and vegetables per day.54,59,74,77
Recent findings of a longitudinal study of 260 breast cancer survivors tracked over the course of 2 years suggests that although initial dietary changes such as reduced fat and increased fruit and vegetable intakes may occur postdiagnosis, significant recidivism in fat intake occurs over time and fruit and vegetable intake, although increased, still remains suboptimal in a majority of survivors (75.8%).83 Furthermore, a large proportion of successfully treated cancer survivors are overweight or obese, 11,14,15,18,20,22,48,74 with body weight increasing consistently and significantly over time,83 thus arguing for interventions aimed at energy restriction and/or increased physical activity.
Data regarding physical activity and cancer survivors are mixed, with some studies suggesting higher levels of physical activity,54,59,68,74,79 some suggesting no differences,57,67,75 and some suggesting less.58 Data from a study by Salminen et al76 indicate that 27% of survivors report more physical activity after diagnosis, whereas 10% report less after diagnosis. Interpretation of data is complicated further by recent shifts in guidelines. For example, a 2000 study by Demark-Wahnefried et al59 suggests that a majority of breast and prostate cancer survivors “routinely exercise.” However, this study was conducted at a time when the physical-activity guidelines were 20 minutes per day, 3 times per week, not the 30 minutes (American College of Sports Medicine) or the 60 minutes (Institute of Medicine) on most days per week currently recommended.84,85 Thus, it is doubtful whether a majority of survivors would be classified as “active” using these new criteria, although a recent study of breast, colon, and prostate cancer survivors by Blanchard et al54 suggests that 70% of survivors report exercising 30 minutes per day at least 5 days per week. As in the general population, cancer survivors frequently overestimate their level of physical activity; thus, these data are suspect.86,87 Regardless, it should be recognized that the impact of the media and the establishment of a role model may bring positive, sweeping change, as evidenced by the recent findings of Thorsen et al.79 In this study of testicular cancer survivors, an increased odds ratio of 1.32 (95% CI, 1.10 to 1.58) for physical activity was found, a result attributed to Lance Armstrong (testicular cancer survivor and seven-time winner of the Tour de France), because cycling accounted for much of the increased activity.
Although a substantial proportion of cancer survivors spontaneously initiate positive behavioral changes, many do not. Males and those who are less educated, over the age of 65, or who live in urban areas are less likely to either undertake healthful changes in behavior54,59,64,73 or maintain them.55,65,88 Data originating from the area of mammography screening clearly show that physicians are among the most powerful catalysts for promoting behavior change89,90 and therefore may be optimally positioned to deliver guidance regarding health promotion. Indeed in a recent randomized controlled trial (N = 450) conducted by Jones et al,91 breast cancer patients randomly assigned to an arm receiving an oncologist's recommendation to exercise reported a mean increase of 3.4 Metabolic Equivalents per week, compared with those not receiving a similar message (P = .011). Current reports, however, suggest that only approximately 20% of oncology care physicians provide assistance in this area—an unmet need that may be driven by competing treatment or health concerns, time constraints, or an unsurety regarding the delivery of appropriate health-behavior messages and their potential impact on health outcomes.54,59,92,93 Abbreviated reviews in areas of smoking cessation, diet, and exercise follow in an effort to inform oncologists of lifestyle interventions that have been conducted to date and their associated outcomes.
MacVicar and Winningham94 were the first to report results of a lifestyle intervention aimed at improving health among cancer survivors. Their study, which measured changes in functional capacity with an exercise program, was typical of many of the earlier behavioral studies that targeted cancer survivors (ie, studies on small samples, using quasi-experimental designs and using an amalgam of outcomes, including some that solely measured treatment-related issues such as nausea). During the ensuing years, the field has evolved, sample sizes of studies have increased, the rigor of experimental design has improved, and the breadth of studies has expanded. Although most of these behavioral interventions are focused on improving QOL and other psychosocial end points and are not included in this review, several are aimed specifically at improving physical health or functional outcomes. To date, published reports describe 20 exercise interventions,87,94-112 11 diet-related interventions (not including those limited to dietary supplements or single nutrients),113-123 two diet and exercise interventions,124,125 six behavioral-based smoking-cessation interventions,126-131 and one sun-protection intervention.132 Brief summaries of studies that used a randomized design are listed in Table 2.
Smoking is well recognized for its causal association with lung and head and neck cancers, as well as CVD; however, less well known is its association with cancers of the cervix, bladder, and kidney.133 Thus, smoking cessation is of paramount importance for primary prevention and is essential also for preventing recurrence among those with tobacco-related carcinomas.134 Although one would expect that the cancer diagnosis may provide a “teachable moment,”6 Sanderson-Cox et al129 observed comparable uptake of a brief smoking-cessation intervention delivered by a nicotine-dependence counselor in both lung cancer and nonlung cancer patients (ie, 22% v 14% abstinence rates, respectively; no significant difference in adjusted analyses). Similarly, no observed differences were seen between quit rates of head and neck cancer patients who received standardized advice to quit versus those who received more intensive counseling by their surgeons.128 Schnoll et al130 also observed no significant differences in quit rates when they compared cancer patients who received standard of care to those who received a brief (<5-minute) smoking-cessation intervention from their physician. Taken together, these findings suggest that proven smoking-cessation interventions may be appropriate for use among cancer survivors; however, more work is needed to develop effective interventions for use in these high-risk and resistant populations.134
To date, there have been 11 reported dietary-intervention studies among cancer survivors. These have been divided equally across the following areas: (1) energy restriction115,116,119; (2) fat restriction113,114,118,123; and (3) a plant-based, low-fat diet.117,120,121,122 Dietary intake has been reported in seven of these studies, and findings suggest that interventions have been largely effective in promoting dietary change—a change that is confirmed in two of the three studies in which biomarkers of intake were collected (ie, serum carotenoids as a measure of fruit and vegetable intake).121,122 In eight studies, body weight was listed as an end point,113-119,123 and significant improvement in weight status was reported in all but one of these studies.119 Hormonal end points were measured in two of three studies that explored the effects of low-fat diet interventions, and findings suggest that estrogen profiles improved overall.113,123 Therefore, these dietary interventions seem successful, at least with respect to the end points considered. However, most dietary interventions to date have relied on intensive, in-person, individualized counseling sessions delivered by trained nutritionists and therefore are resource intensive. Kristal et al,118 Djuric et al,116 and Pierce et al121,122 have reported success in using less intensive interventions that are either delivered by trained volunteer staff, by commercial institutions (ie, Weight Watchers), or through telephone counseling, although trained nutritionists were still an important component of these interventions.
Combined approaches using individualized counseling, group classes, and telephone counseling have served as the delivery channels for two large, multisite, randomized controlled trials that should produce results regarding whether modifications in diet affect disease-free and/or overall survival. Published findings of the Women's Intervention Nutrition Study (a trial that will test the effect of a low-fat diet [< 15% of total calories] in approximately 2,500 postmenopausal breast cancer patients) are anticipated soon.135 Results of the Women's Healthy Eating and Living Study, a trial that will test the effect of more global dietary change (ie, daily intakes of five vegetable servings, 16 ounces of vegetable juice, three fruit servings, 15% to 20% energy from fat, and 30 g of dietary fiber) in 3,088 pre- and postmenopausal breast cancer patients are anticipated in 2006.121,122 Although preliminary findings suggest that these interventions have been effective in promoting biomarker-validated dietary change,121 the impact of dietary change on ultimate end points of disease progression and recurrence has yet to be determined. The results of both of these trials will be instrumental in filling the void that currently exists regarding the impact of dietary interventions on disease-free survival.
Although problems with anorexia and cachexia may continue among some groups of survivors such as those with head and neck cancers,14 for many survivors avoiding or controlling obesity is a far greater problem. 11,14,15,18,20,22,48,74 Here, multiple behavior interventions that use a comprehensive approach to energy balance and include both diet and exercise components may have the potential to be more effective than interventions relying on either component alone.136 In their evaluation of a diet and exercise intervention aimed at early-stage breast cancer patients, Goodwin et al124 found that aerobic exercise was the strongest predictor of weight loss. To date, findings of only two multiple behavior interventions among survivors have been reported, and both used quasi-experimental designs.124,125 There are, however, at least two studies that are currently in the field.7,8
Exercise-intervention trials have comprised the majority of the behavioral interventions conducted among cancer survivors to date. Many of these trials were undertaken to determine whether increased physical activity could relieve treatment-related nausea and fatigue or were aimed at improving QOL. Recent reviews by Courneya,50 Courneya and Friedenreich,51 Pinto and Maruyama,52 Schwartz,53 and the Agency for Healthcare Research and Quality136 find that exercise is consistently associated with improved QOL. The Agency for Healthcare Research and Quality review, as well as recent reviews by McTiernan49 and Galvao and Newton,137 suggest that exercise interventions have been effective also in improving physical functioning (ie, oxygen capacity, other fitness or strength measures, flexibility, and global health), anthropometric measures (ie, weight status, body fat, and waist and hip circumferences), and health-related biomarkers (ie, blood pressure, heart rate, hemoglobin concentration, and circulating hormonal levels). Increased engagement in social activities and less sleep disturbance have been reported also.94,95 A recent study by Fairey et al104 also suggests that exercise has a favorable effect on a subset of markers associated with metabolic syndrome such as insulin-like growth factor 1 and insulin-like growth factor-binding protein-3. Although it is clear that exercise is associated with many benefits for the cancer survivor, the impact of exercise on survival (whether overall or disease free) remains to be determined.49,136-138 Additionally, it still is unknown how soon after diagnosis exercise should be promoted.136 Although reviews suggest that early intervention has positive effects on QOL and several health outcomes, there is the potential, at least theoretically, for exercise to increase free-radical formation, reduce white blood cell counts, and interfere with treatment.49 Pre-existing conditions (eg, arthritis, chronic obstructive pulmonary disease) and adverse effects of treatment (eg, cardiac compromise secondary to anthracycline exposure) also may warrant caution in what types of exercise and how aggressively a survivor should pursue exercise after treatment. Thus, more research is necessary, as is prudent guidance for pursuing exercise in a moderate and stepped-dose approach, especially if undertaken during active treatment.49-53
As cancer joins the ranks of chronic disease, oncologists will increasingly find themselves at a juncture with their patients, as interests turn from acute care to managing long-term health. Cancer survivors thus present us with an exceptional opportunity to target primary, secondary, and tertiary prevention strategies capable of effecting beneficial outcomes at all three levels of prevention. A cancer survivor may simultaneously be a good candidate to receive (1) primary prevention messages such as reducing saturated fats in the diet and obesity management to prevent coronary heart disease and other potential comorbidities, (2) secondary prevention strategies such as screening for breast cancer in females previously treated for Hodgkin's Disease or regular screening for other secondary malignant neoplasms among those diagnosed and treated for cancer, and (3) tertiary prevention methods such as the early detection and management of late effects of cancer treatment such as heart disease after adriamycin chemotherapy. Such strategies may overlap; for example, the use of DEXRA or Zinecard in relation to adriamycin-based chemotherapy may have implications in both primary and tertiary prevention. Messages and strategies also must be tempered and are affected by multiple mediating or moderating factors such as age (current and at diagnosis/treatment), genetic risk profile (family history), concurrent comorbidities, and so on. Figure 1 presents a model of some of the more salient and complex associations between prevention strategies, attendant targets, and potential moderators or mediators. A recent review by Kattlove and Wynn139 also can help guide oncologists in providing quality continuing care for their patients—care that spans a broad spectrum of medical areas ranging from surveillance to genetic susceptibility. As noted, cancer survivors increasingly are looking to their oncology care providers for counsel and guidance with respect to lifestyle change that will improve their prospects of a healthier life and possibly a longer one as well.95,139 Although complete data regarding lifestyle change among cancer survivors have yet to be determined and there remains an unmet need for behavioral interventions with proven efficacy in various cancer populations,140 the oncologist nonetheless can make use of extant data to inform practice and also should be attentive to new developments in the field. Physician-based strategies also can be adopted from those that currently exist in primary care.141-148 Additionally, the development of partnerships with behavioral researchers, as well as allied health personnel, may be helpful in overcoming barriers of limited time, resources, and expertise in delivering effective lifestyle interventions.149 A resource list of organizations that provide sound information regarding lifestyle behaviors also is provided in Table 3 to facilitate this exchange. For decades the cancer diagnosis has been acknowledged as a life-changing event. It is time for oncology care providers not only to lead their patients away from disease but also to capitalize on the teachable moment that cancer provides and guide their patients to better health.
Supported by National Institutes of Health grant Nos. CA81191 (W.D.-W.), CA92468 (W.D.-W.), CA106919 (W.D.-W.), and The Susan G. Komen Foundation (W.D.-W. and N.M.A.), American Cancer Society (B.M.P.), and The Lance Armstrong Foundation (B.M.P.).
Parts of this article have been used to develop a chapter (coauthors: W.D.-W. and N.M.A.) within a planned volume entitled “Handbook of Behavioral Science and Cancer” to be published by the American Psychological Association later this year.
Authors' Disclosures of Potential Conflicts of Interest
The authors indicated no potential conflicts of interest.