A Meta-analysis of the Association Between Physical Activity and Breast Cancer Mortality.

BACKGROUND: There are conflicting data on the association between physical activity (PA) intensity and amount and prognosis of breast cancer. It is unknown whether increasing or decreasing PA is associated with all-cause mortality. OBJECTIVE: The purpose of this study was to estimate the associations between PA and the risk of mortality. METHODS: MEDLINE and EMBASE were used to find eligible studies published from January 1970 to March 2017 for this meta-analysis. We included 24 studies, with a total of 144 224 patients and follow-up periods ranging from 1.9 to 12.7 years. We categorized the amount of PA as low (<300 min/wk), moderate (300-500 min/wk), and high (>500 min/wk). RESULTS: We found that high amounts of PA had an inverse relationship with breast-cancer-specific mortality and all-cause morality. Patients who decreased PA after diagnosis showed poorer all-cause mortality, whereas patients who increased PA postdiagnosis had a favorable association with all-cause mortality. Last, patients who met PA guidelines after diagnosis had a lower breast-cancer-specific mortality and all-cause mortality. CONCLUSION: Physical activity may play a pivotal role in reducing the risk of death. Getting at least 300 min/wk of moderate-intensity PA will help improve the risk of breast cancer death. IMPLICATIONS FOR PRACTICE: Participating in PA is an essential factor in breast cancer care that extends throughout the life span of cancer survivors. Higher levels of PA than current PA guidelines should be recommended to cancer patients.