Kerry S. Courneya

Nutrition and physical activity guidelines for cancer survivors

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An update of controlled physical activity trials in cancer survivors: a systematic review and meta-analysis

IntroductionApproximately 11.1 million cancer survivors are alive in the United States. Activity prescriptions for cancer survivors rely on evidence as to whether exercise during or after treatment results in improved health outcomes. This systematic review and meta-analysis evaluates the extent to which physical activity during and post treatment is appropriate and effective across the cancer control continuum.MethodsA systematic quantitative review of the English language scientific literature searched controlled trials of physical activity interventions in cancer survivors during and post treatment. Data from 82 studies were abstracted, weighted mean effect sizes (WMES) were calculated from 66 high quality studies, and a systematic level of evidence criteria was applied to evaluate 60 outcomes. Reports of adverse events were abstracted from all studies.ResultsQuantitative evidence shows a large effect of physical activity interventions post treatment on upper and lower body strength (WMES = 0.99 & 0.90, p < 0.0001 & 0.024, respectively) and moderate effects on fatigue and breast cancer-specific concerns (WMES = −0.54 & 0.62, p = 0.003 & 0.003, respectively). A small to moderate positive effect of physical activity during treatment was seen for physical activity level, aerobic fitness, muscular strength, functional quality of life, anxiety, and self-esteem. With few exceptions, exercise was well tolerated during and post treatment without adverse events.ConclusionsCurrent evidence suggests many health benefits from physical activity during and post cancer treatments. Additional studies are needed in cancer diagnoses other than breast and with a focus on survivors in greatest need of improvements for the health outcomes of interest.

Effects of exercise on breast cancer patients and survivors: a systematic review and meta-analysis

Background: Physical exercise has been identified as a potential intervention to improve quality of life in women with breast cancer. We sought to summarize the available evidence concerning the effects of exercise on breast cancer patients and survivors. Methods: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL, PsychINFO, CancerLit, PEDro and SportDiscus as well as conference proceedings, clinical practice guidelines and other unpublished literature resources. We included only randomized controlled trials that examined exercise interventions for breast cancer patients or survivors with quality of life, cardiorespiratory fitness or physical functioning as primary outcomes. We also extracted data on symptoms of fatigue, body composition and adverse effects. Results: Of 136 studies identified, 14 met all the inclusion criteria. Despite significant heterogeneity and relatively small samples, the point estimates in terms of the benefits of exercise for all outcomes were positive even when statistical significance was not achieved. Exercise led to statistically significant improvements in quality of life as assessed by the Functional Assessment of Cancer Therapy–General (weighted mean difference [WMD] 4.58, 95% confidence interval [CI] 0.35 to 8.80) and Functional Assessment of Cancer Therapy–Breast (WMD 6.62, 95% CI 1.21 to 12.03). Exercise also led to significant improvements in physical functioning and peak oxygen consumption and in reducing symptoms of fatigue. Interpretation: Exercise is an effective intervention to improve quality of life, cardiorespiratory fitness, physical functioning and fatigue in breast cancer patients and survivors. Larger trials that have a greater focus on study quality and adverse effects and that examine the long-term benefits of exercise are needed for this patient group.

Effects of Aerobic and Resistance Exercise in Breast Cancer Patients Receiving Adjuvant Chemotherapy: A Multicenter Randomized Controlled Trial

PURPOSE Breast cancer chemotherapy may cause unfavorable changes in physical functioning, body composition, psychosocial functioning, and quality of life (QOL). We evaluated the relative merits of aerobic and resistance exercise in blunting these effects. PATIENTS AND METHODS We conducted a multicenter randomized controlled trial in Canada between 2003 and 2005 that randomly assigned 242 breast cancer patients initiating adjuvant chemotherapy to usual care (n = 82), supervised resistance exercise (n = 82), or supervised aerobic exercise (n = 78) for the duration of their chemotherapy (median, 17 weeks; 95% CI, 9 to 24 weeks). Our primary end point was cancer-specific QOL assessed by the Functional Assessment of Cancer Therapy-Anemia scale. Secondary end points were fatigue, psychosocial functioning, physical fitness, body composition, chemotherapy completion rate, and lymphedema. RESULTS The follow-up assessment rate for our primary end point was 92.1%, and adherence to the supervised exercise was 70.2%. Unadjusted and adjusted mixed-model analyses indicated that aerobic exercise was superior to usual care for improving self-esteem (P = .015), aerobic fitness (P = .006), and percent body fat (adjusted P = .076). Resistance exercise was superior to usual care for improving self-esteem (P = .018), muscular strength (P < .001), lean body mass (P = .015), and chemotherapy completion rate (P = .033). Changes in cancer-specific QOL, fatigue, depression, and anxiety favored the exercise groups but did not reach statistical significance. Exercise did not cause lymphedema or adverse events. CONCLUSION Neither aerobic nor resistance exercise significantly improved cancer-specific QOL in breast cancer patients receiving chemotherapy, but they did improve self-esteem, physical fitness, body composition, and chemotherapy completion rate without causing lymphedema or significant adverse events.

Resistance Exercise in Men Receiving Androgen Deprivation Therapy for Prostate Cancer

PURPOSE Androgen deprivation therapy is a common treatment in men with prostate cancer that may cause fatigue, functional decline, increased body fatness, and loss of lean body tissue. These physical changes can negatively affect health-related quality of life. Resistance exercise may help to counter some of these side effects by reducing fatigue, elevating mood, building muscle mass, and reducing body fat. METHODS In a two-site study, 155 men with prostate cancer who were scheduled to receive androgen deprivation therapy for at least 3 months after recruitment were randomly assigned to an intervention group that participated in a resistance exercise program three times per week for 12 weeks (82 men) or to a waiting list control group (73 men). The primary outcomes were fatigue and disease-specific quality of life as assessed by self-reported questionnaires after 12 weeks. Secondary outcomes were muscular fitness and body composition. RESULTS Men assigned to resistance exercise had less interference from fatigue on activities of daily living (P =.002) and higher quality of life (P =.001) than men in the control group. Men in the intervention group demonstrated higher levels of upper body (P =.009) and lower body (P <.001) muscular fitness than men in the control group. The 12-week resistance exercise intervention did not improve body composition as measured by changes in body weight, body mass index, waist circumference, or subcutaneous skinfolds. CONCLUSION Resistance exercise reduces fatigue and improves quality of life and muscular fitness in men with prostate cancer receiving androgen deprivation therapy. This form of exercise can be an important component of supportive care for these patients.

Randomized Controlled Trial of Exercise Training in Postmenopausal Breast Cancer Survivors: Cardiopulmonary and Quality of Life Outcomes

PURPOSE To determine the effects of exercise training on cardiopulmonary function and quality of life (QOL) in postmenopausal breast cancer survivors who had completed surgery, radiotherapy, and/or chemotherapy with or without current hormone therapy use. METHODS Fifty-three postmenopausal breast cancer survivors were randomly assigned to an exercise (n = 25) or control (n = 28) group. The exercise group trained on cycle ergometers three times per week for 15 weeks at a power output that elicited the ventilatory equivalent for carbon dioxide. The control group did not train. The primary outcomes were changes in peak oxygen consumption and overall QOL from baseline to postintervention. Peak oxygen consumption was assessed by a graded exercise test using gas exchange analysis. Overall QOL was assessed by the Functional Assessment of Cancer Therapy-Breast scale. RESULTS Fifty-two participants completed the trial. The exercise group completed 98.4% of the exercise sessions. Baseline values for peak oxygen consumption (P =.254) and overall QOL (P =.286) did not differ between groups. Peak oxygen consumption increased by 0.24 L/min in the exercise group, whereas it decreased by 0.05 L/min in the control group (mean difference, 0.29 L/min; 95% confidence interval [CI], 0.18 to 0.40; P <.001). Overall QOL increased by 9.1 points in the exercise group compared with 0.3 points in the control group (mean difference, 8.8 points; 95% CI, 3.6 to 14.0; P =.001). Pearson correlations indicated that change in peak oxygen consumption correlated with change in overall QOL (r = 0.45; P <.01). CONCLUSION Exercise training had beneficial effects on cardiopulmonary function and QOL in postmenopausal breast cancer survivors.

Controlled Physical Activity Trials in Cancer Survivors: A Systematic Review and Meta-analysis

Background: Approximately 9.8 million cancer survivors are alive in the United States today. Enthusiasm for prescribing physical activity for cancer survivors depends on evidence regarding whether physical activity during or after completion of treatment results in improved outcomes such as cardiorespiratory fitness, fatigue, symptoms, quality of life, mental health, or change in body size. Methods: A systematic qualitative and quantitative review of the English language scientific literature identified controlled trials of physical activity interventions in cancer survivors during and after treatment. Data from 32 studies were abstracted, weighted mean effect sizes (WMES) were calculated from the 22 high-quality studies, and a systematic level of evidence criteria was applied to evaluate 25 outcomes. Results: There was qualitative and quantitative evidence of a small to moderate effect of physical activity interventions on cardiorespiratory fitness (WMES = 0.51 and 0.65 during and after treatment respectively, P < 0.01), physiologic outcomes and symptoms during treatment (WMES = 0.28, P < 0.01 and 0.39, P < 0.01, respectively), and vigor posttreatment (WMES = 0.83, P = 0.04). Physical activity was well tolerated in cancer survivors during and after treatment, but the available literature does not allow conclusions to be drawn regarding adverse events from participation. Conclusions: Physical activity improves cardiorespiratory fitness during and after cancer treatment, symptoms and physiologic effects during treatment, and vigor posttreatment. Additional physical activity intervention studies are needed to more firmly establish the range and magnitude of positive effects of physical activity among cancer survivors.

Nutrition and Physical Activity During and After Cancer Treatment: An American Cancer Society Guide for Informed Choices†

Cancer survivors are often highly motivated to seek information about food choices, physical activity, and dietary supplement use to improve their treatment outcomes, quality of life, and survival. To address these concerns, the American Cancer Society (ACS) convened a group of experts in nutrition, physical activity, and cancer to evaluate the scientific evidence and best clinical practices related to optimal nutrition and physical activity after the diagnosis of cancer. This report summarizes their findings and is intended to present health care providers with the best possible information from which to help cancer survivors and their families make informed choices related to nutrition and physical activity. The report discusses nutrition and physical activity issues during the phases of cancer treatment and recovery, living after recovery from treatment, and living with advanced cancer; select nutrition and physical activity issues such as body weight, food choices, and food safety; issues related to select cancer sites; and common questions about diet, physical activity, and cancer survivorship.

Physical Activity, Biomarkers, and Disease Outcomes in Cancer Survivors: A Systematic Review

BACKGROUND Cancer survivors often seek information about how lifestyle factors, such as physical activity, may influence their prognosis. We systematically reviewed studies that examined relationships between physical activity and mortality (cancer-specific and all-cause) and/or cancer biomarkers. METHODS We identified 45 articles published from January 1950 to August 2011 through MEDLINE database searches that were related to physical activity, cancer survival, and biomarkers potentially relevant to cancer survival. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement to guide this review. Study characteristics, mortality outcomes, and biomarker-relevant and subgroup results were abstracted for each article that met the inclusion criteria (ie, research articles that included participants with a cancer diagnosis, mortality outcomes, and an assessment of physical activity). RESULTS There was consistent evidence from 27 observational studies that physical activity is associated with reduced all-cause, breast cancer-specific, and colon cancer-specific mortality. There is currently insufficient evidence regarding the association between physical activity and mortality for survivors of other cancers. Randomized controlled trials of exercise that included biomarker endpoints suggest that exercise may result in beneficial changes in the circulating level of insulin, insulin-related pathways, inflammation, and, possibly, immunity; however, the evidence is still preliminary. CONCLUSIONS Future research directions identified include the need for more observational studies on additional types of cancer with larger sample sizes; the need to examine whether the association between physical activity and mortality varies by tumor, clinical, or risk factor characteristics; and the need for research on the biological mechanisms involved in the association between physical activity and survival after a cancer diagnosis. Future randomized controlled trials of exercise with biomarker and cancer-specific disease endpoints, such as recurrence, new primary cancers, and cancer-specific mortality in cancer survivors, are warranted.

Investigating multiple components of attitude, subjective norm, and perceived control: An examination of the theory of planned behaviour in the exercise domain

The presence of two subcomponents within each theory of planned behaviour (TPB) concept of attitude (affective and instrumental), subjective norm (injunctive and descriptive), and PBC (self-efficacy and controllability) has been widely supported. However, research has not examined whether the commonality of variance between these components (i.e. a general factor) or the specificity of variance within the subcomponents influences intention and behaviour. Therefore, the purpose of this study was to examine the optimal conceptualization of either two subcomponents or a general common factor for each TPB concept within an omnibus model. Further, to test whether conceptualizations may differ by population even within the same behavioural domain, we examined these research questions with 300 undergraduates (M age = 20) and 272 cancer survivors (M age = 61) for exercise behaviour. Results identified that a general subjective norm factor was an optimal predictive conceptualization over two separate injunctive and descriptive norm components. In contrast, a specific self-efficacy component, and not controllability or a general factor of PBC, predicted intention optimally for both samples. Finally, optimal models of attitude differed between the populations, with a general factor best predicting intention for undergraduates but only affective attitude influencing intention for cancer survivors. The findings of these studies underscore the possibility for optimal tailored interventions based on population and behaviour. Finally, a discussion of the theoretical ambiguity of the PBC concept led to suggestions for future research and possible re-conceptualization.