Key clinical point: Higher levels of leisure-time physical activity reduced the risk for premenopausal breast cancer (BC) significantly, with more prominent effects observed for human epidermal growth factor receptor 2 (HER2)-enriched BC.
Major finding: At a median follow-up of 11.5 years, higher vs lower levels (90 th vs 10 th percentile) of leisure-time physical activity were associated with a 10% reduced risk for overall BC (adjusted hazard ratio [aHR] 0.90; P < .001) and a substantial 45% reduction in the risk for HER2-enriched BC (aHR 0.55; 95% CI 0.37-0.82).
Study details: Findings are from a pooled analysis of the data from 19 prospective cohorts that included a total of 547,601 premenopausal women with 10,231 incident cases of in situ or invasive BC.
Disclosures: This study was supported by the Intramural Research Program of the US National Cancer Institute and US National Institutes of Health, and other sources. Some authors declared employment with; holding patents, stocks, and other ownership interests in; serving in consulting or advisory roles for; or receiving honoraria or research funding from various sources.
Source: Timmins IR et al. International pooled analysis of leisure-time physical activity and premenopausal breast cancer in women from 19 cohorts. J Clin Oncol. 2023 (Dec 11). doi: 10.1200/JCO.23.01101