McCann, William

Abstract Background Although physical activity has been consistently associated with reduced breast cancer mortality, evidence is largely based on data collected at one occasion. We examined how pre- and postdiagnosis physical activity was associated with survival outcomes in high-risk breast cancer patients. Methods Included were 1340 patients enrolled in the Diet, Exercise, Lifestyle and Cancer Prognosis (DELCaP) Study, a prospective study of lifestyle and prognosis ancillary to a SWOG clinical trial (S0221). Activity before diagnosis, during treatment, and at 1- and 2-year intervals after enrollment was collected. Patients were categorized according to the Physical Activity Guidelines for Americans as meeting the minimum guidelines (yes/no) and incrementally as inactive, low active, moderately active (meeting the guidelines), or high active. Results In joint-exposure analyses, patients meeting the guidelines before and 1 year after diagnosis experienced statistically significant reductions in hazards of recurrence (hazard ratio [HR] = 0.59, 95% confidence interval [CI] = 0.42 to 0.82) and mortality (HR = 0.51, 95% CI = 0.34–0.77); associations were stronger at 2-year follow-up for recurrence (HR = 0.45, 95% CI = 0.31 to 0.65) and mortality (HR = 0.32, 95% CI = 0.19 to 0.52). In time-dependent analyses, factoring in activity from all time points, we observed striking associations with mortality for low- (HR = 0.41, 95% CI = 0.24 to 0.68), moderate- (HR = 0.42, 95% CI = 0.23 to 0.76), and high-active patients (HR = 0.31, 95% CI = 0.18 to 0.53). Conclusions Meeting the minimum guidelines for physical activity both before diagnosis and after treatment appears to be associated with statistically significantly reduced hazards of recurrence and mortality among breast cancer patients. When considering activity from all time points, including during treatment, lower volumes of regular activity were associated with similar overall survival advantages as meeting and exceeding the guidelines.

PURPOSE Despite reported widespread use of dietary supplements during cancer treatment, few empirical data with regard to their safety or efficacy exist. Because of concerns that some supplements, particularly antioxidants, could reduce the cytotoxicity of chemotherapy, we conducted a prospective study ancillary to a therapeutic trial to evaluate associations between supplement use and breast cancer outcomes. METHODS Patients with breast cancer randomly assigned to an intergroup metronomic trial of cyclophosphamide, doxorubicin, and paclitaxel were queried on their use of supplements at registration and during treatment (n =1,134). Cox proportional hazards regression adjusting for clinical and lifestyle variables was used. Recurrence and survival were indexed at 6 months after enrollment using a landmark approach. RESULTS There were indications that use of any antioxidant supplement (vitamins A, C, and E; carotenoids; coenzyme Q10) both before and during treatment was associated with an increased hazard of recurrence (adjusted hazard ratio [adjHR], 1.41; 95% CI, 0.98 to 2.04; P = .06) and, to a lesser extent, death (adjHR, 1.40; 95% CI, 0.90 to 2.18; P = .14). Relationships with individual antioxidants were weaker perhaps because of small numbers. For nonantioxidants, vitamin B12 use both before and during chemotherapy was significantly associated with poorer disease-free survival (adjHR, 1.83; 95% CI, 1.15 to 2.92; P < .01) and overall survival (adjHR, 2.04; 95% CI, 1.22 to 3.40; P < .01). Use of iron during chemotherapy was significantly associated with recurrence (adjHR, 1.79; 95% CI, 1.20 to 2.67; P < .01) as was use both before and during treatment (adjHR, 1.91; 95% CI, 0.98 to 3.70; P = .06). Results were similar for overall survival. Multivitamin use was not associated with survival outcomes. CONCLUSION Associations between survival outcomes and use of antioxidant and other dietary supplements both before and during chemotherapy are consistent with recommendations for caution among patients when considering the use of supplements, other than a multivitamin, during chemotherapy.