Physical activity, diet, adiposity and female breast cancer prognosis: a review of the epidemiologic literature.

Given the increasing numbers of long-term survivors of breast cancer, research specific to prevention of recurrence, new breast cancer events, and mortality is of considerable public health importance. The objective of this report is to present a review of the published epidemiologic research on lifestyle and breast cancer outcomes among women with a history of breast cancer. This review focused on physical activity, diet, and adiposity; and the primary outcomes were additional breast cancer events and mortality. The most consistent finding from observational studies was that adiposity was associated with a 30% increased risk of mortality. Although the observational data were not as consistent (or abundant), physical activity appeared to be associated with a 30% decreased risk of mortality. These data do not indicate that alcoholic drinks are a risk factor. Based only on the observational studies, total dietary fat appeared to be a risk factor, fiber was protective, and information on micronutrients and specific foods was sparse. However, the null results of 2 dietary intervention trials in survivors suggests that lowering fat intake or increasing consumption of fruits, vegetables, and fiber will not lead to improved prognosis in breast cancer survivors. Given that a high proportion of breast cancer patients appear to be both sedentary and obese/overweight, clinical trials are needed to investigate whether the combination of increased physical activity and reduced adiposity can improve breast cancer prognosis.

Community-based aquatic exercise and quality of life in persons with osteoarthritis.

PURPOSE: To evaluate the effectiveness of a community-based aquatic exercise program for improved quality of life among persons with osteoarthritis. METHOD: Two hundred forty-nine adults with osteoarthritis were enrolled in a 20-wk randomized controlled trial of a preexisting community-based aquatic exercise program versus control. Intervention group participants (n = 125) were asked to attend at least two aquatic exercise sessions per week. Control group participants (n = 124) were asked to maintain their usual activity levels. Demographics were collected at baseline, and patient-reported outcomes were collected at baseline and after 10 and 20 wk. Depressive symptoms, self-efficacy for pain and symptom control, physical impairment, and activity limitation were tested as potential mediators of the relationship between aquatic exercise and perceived quality of life (PQOL). Body mass index (BMI), ethnicity, self-rated health, and comorbidity were tested as possible moderators. RESULTS: Aquatic exercise had a positive impact on PQOL scores (P < 0.01). This effect was moderated by BMI (P < 0.05) such that benefits were observed among obese participants (BMI >or= 30), but not among normal weight or overweight participants. None of the tested variables were found to mediate the relationship between aquatic exercise and PQOL scores. CONCLUSIONS: Given the availability of existing community aquatics programs, aquatic exercise offers a therapeutic and pragmatic option to promote quality of life among individuals who are living with both obesity and osteoarthritis. Future investigation is needed to replicate these findings and develop strategies to increase long-term participation in aquatics programs.

Exercise improves body fat, lean mass, and bone mass in breast cancer survivors.

Given the negative effects of a breast cancer diagnosis and its treatments on body weight and bone mass, we investigated the effects of a 6-month randomized controlled aerobic exercise intervention vs. usual care on body composition in breast cancer survivors. Secondary aims were to examine the effects stratified by important prognostic and physiologic variables. Seventy-five physically inactive postmenopausal breast cancer survivors were recruited through the Yale-New Haven Hospital Tumor Registry and randomly assigned to an exercise (n = 37) or usual care (n = 38) group. The exercise group participated in 150 min/week of supervised gym- and home-based moderate-intensity aerobic exercise. The usual care group was instructed to maintain their current physical activity level. Body composition was assessed at baseline and 6-months through dual-energy X-ray absorptiometry (DXA) by one radiologist blinded to the intervention group of the participants. On an average, exercisers increased moderate-intensity aerobic exercise by 129 min/week over and above baseline levels compared with 45 min/week among usual care participants (P < 0.001). Exercisers experienced decreases in percent body fat (P = 0.0022) and increases in lean mass (P = 0.047) compared with increases in body fat and decreases in lean mass in usual care participants. Bone mineral density (BMD) was also maintained among exercisers compared with a loss among usual care participants (P = 0.043). In summary, moderate-intensity aerobic exercise, such as brisk walking, produces favorable changes in body composition that may improve breast cancer prognosis.

Adherence to a randomized controlled trial of aerobic exercise in breast cancer survivors: the Yale exercise and survivorship study.

PURPOSE: To examine predictors of exercise adherence in breast cancer survivors. METHODS: Seventy-five breast cancer survivors were randomly assigned to exercise (n = 37) or usual care (n = 38). Demographic, prognostic, physiologic, and psychosocial information was collected at baseline and 6 months. The exercise goal was 30 min of exercise 5 days/week for 6 months. RESULTS: Women randomized to exercise participated in moderate-intensity recreational exercise for 123 +/- 52 min/week (81% of the prescribed 150 min/week) over 6 months. Baseline variables associated with better adherence were lower body mass index (BMI), smaller waist circumference, higher amounts of physical activity 6 months prior to enrollment, being in the preparation vs. contemplation Stage of Change and higher FACT-B breast cancer subscale score. After adjusting for these variables, lower BMI and higher Stage of Change continued to be associated with better adherence (p < 0.05). CONCLUSIONS: Future studies of exercise and breast cancer prognosis should target obese women for participation, as well as women just beginning to contemplate participation and its benefits after a cancer diagnosis.

Exercise and quality of life during and after treatment for breast cancer: results of two randomized controlled trials.

OBJECTIVE: To determine the effect of exercise on quality of life in (a) a randomized controlled trial of exercise among recently diagnosed breast cancer survivors undergoing adjuvant therapy and (b) a similar trial among post-treatment survivors. METHODS: Fifty newly diagnosed breast cancer survivors were recruited through a hospital-based tumor registry and randomized to a 6-month, home-based exercise program (n=25) or a usual care group (n=25). In a separate trial, 75 post-treatment survivors were randomized to a 6-month, supervised exercise intervention (n=37) or to usual care (n=38). Participants in both studies completed measures of happiness, depressive symptoms, anxiety, stress, self-esteem, and quality of life at baseline and 6 months. RESULTS: Forty-five participants completed the trial for newly diagnosed survivors and 67 completed the trial for post-treatment survivors. Good adherence was observed in both studies. Baseline quality of life was similar for both studies on most measures. Exercise was not associated with quality of life benefits in the full sample of either study; however exercise was associated with improved social functioning among post-treatment survivors who reported low social functioning at baseline (p<0.05). CONCLUSIONS: Exercise did not affect quality of life in either recently diagnosed or post-treatment breast cancer survivors; however this may be due in part to relatively high baseline functioning among participants in both studies. Strategies for future research include limiting enrollment to survivors who report reduced quality of life on screening questionnaires and targeting survivor subgroups known to be at particular risk for quality of life impairment.

Randomized controlled trial of aerobic exercise on insulin and insulin-like growth factors in breast cancer survivors: the Yale Exercise and Survivorship study.

BACKGROUND: High insulin and insulin-like growth factor-I (IGF-I) levels may be associated with an increased breast cancer risk and/or death. Given the need to identify modifiable factors that decrease insulin, IGF-I, and breast cancer risk and death, we investigated the effects of a 6-month randomized controlled aerobic exercise intervention versus usual care on fasting insulin, IGF-I, and its binding protein (IGFBP-3) in postmenopausal breast cancer survivors. METHODS: Seventy-five postmenopausal breast cancer survivors were identified from the Yale-New Haven Hospital Tumor Registry and randomly assigned to an exercise (n = 37) or usual care (n = 38) group. The exercise group participated in 150 minutes per week of moderate-intensity aerobic exercise. The usual care group was instructed to maintain their current physical activity level. A fasting blood sample was collected on each study participant at baseline and 6 months. Blood levels of insulin and IGF were measured with ELISA. RESULTS: On average, exercisers increased aerobic exercise by 129 minutes per week compared with 45 minutes per week among usual care participants (P < 0.001). Women randomized to exercise experienced decreases in insulin, IGF-I, and IGFBP-3, whereas women randomized to usual care had increases in these hormones. Between-group differences in insulin, IGF-I, and IGFBP-3 were 20.7% (P = 0.089), 8.9% (P = 0.026), and 7.9% (P = 0.006), respectively. CONCLUSIONS: Moderate-intensity aerobic exercise, such as brisk walking, decreases IGF-I and IGFBP-3. The exercise-induced decreases in IGF may mediate the observed association between higher levels of physical activity and improved survival in women diagnosed with breast cancer.

Recruiting and retaining breast cancer survivors into a randomized controlled exercise trial: the Yale Exercise and Survivorship Study.

BACKGROUND: Given observational findings that physical activity reduces breast cancer risk, improves survival, and improves quality of life in breast cancer survivors, a need has been identified for randomized controlled trials that test the efficacy of exercise on biological mechanisms associated with breast cancer survival. The primary aims of the Yale Exercise and Survivorship Study were to 1) determine the feasibility of recruiting breast cancer survivors into a randomized controlled trial of the effects of exercise on biological markers and/or mechanisms associated with survival, 2) compare the effectiveness of various recruitment strategies on accrual rates and baseline characteristics, and 3) report adherence to the exercise trial. METHODS: Seventy-five postmenopausal breast cancer survivors self-referred into the trial or were recruited through the New Haven Tumor [corrected] Registry and randomly assigned to an exercise (n = 37) or usual-care (n = 38) group. The exercise group participated in 150 min/wk of supervised gym-based and home-based aerobic exercise for 6 months. The usual-care group was instructed to maintain current physical activity level. RESULTS: A total of 75 women (an accrual rate of 9.5%) were randomized to the trial. Rates of accrual were higher for women who self-referred into the study (19.8%) compared with women recruited via the cancer registry (7.6%); however, demographic, physiologic, and prognostic characteristics did not differ between the 2 recruitment strategies. On average, exercisers increased moderate- intensity to vigorous-intensity aerobic exercise by 129 minutes per week compared with 44 minutes per week among usual-care participants (P < .001). Women in the exercise-intervention group increased their average pedometer steps by 1621 steps per day compared with a decrease of 60 steps per day among women in the usual-care group (P < .01). CONCLUSIONS: Findings from this study will provide useful information for investigators who are conducting exercise trials in cancer populations, clinicians who are treating women diagnosed with breast cancer, and exercise professionals who are developing community-based exercise programs for cancer survivors.

Promoting participation in physical activity using framed messages: an application of prospect theory.

OBJECTIVES: Messages designed to motivate participation in physical activity usually emphasize the benefits of physical activity (gain-framed) as well as the costs of inactivity (loss-framed). The framing implications of prospect theory suggest that the effectiveness of these messages could be enhanced by providing gain-framed information only. We compared the effectiveness of gain-, loss-, and mixed-framed messages for promoting moderate to vigorous physical activity. DESIGN: Randomized trial. METHOD: Sedentary, healthy callers to the US National Cancer Institute's Cancer Information Service (N=322) received gain-, loss-, or mixed-framed messages on three occasions (baseline, Week 1, and Week 5). Social cognitive variables and self-reported physical activity were assessed at baseline, Week 2, and Week 9. Separate regression analyses were conducted to examine message effects at each assessment point. RESULTS: At Week 2, gain- and mixed-framed messages resulted in stronger intentions and greater self-efficacy than loss-framed messages. At Week 9, gain-framed messages resulted in greater physical activity participation than loss- or mixed-framed messages. Social cognitive variables at Week 2 did not mediate the Week 9 framing effects on physical activity participation. CONCLUSIONS: Using gain-framed messages exclusively may be a means of increasing the efficacy of physical activity materials.