Cancer
Physical Activity and Breast Cancer Outcomes in the Kaiser Pathways Cohort Study of Breast Cancer Survivors Tanvi Srivastava* Tanvi Srivastava Srivastava Srivastava Srivastava Srivastava UCSF
Physical activity (PA) improves survival and quality of life in breast cancer (BCa) survivors. Yet, limited research to date has been conducted in racially and ethnically diverse cohorts. We examined post-diagnosis PA in relation to cancer outcomes among women with BCa in the Pathways Study at Kaiser Permanente Northern California.
The cohort of 4,504 recently diagnosed BCa patients enrolled between Jan 2006 and May 2013 provided data through surveys and medical records. The cohort was followed for recurrence and mortality outcomes, with follow-up through Dec 31, 2022 for our study. We classified PA at enrollment based on meeting the World Health Organization (WHO) guideline of at least 7.5 MET-hours/week (yes/no). We first explored racial/ethnic variation in participant PA levels using χ2 tests and multinomial logistic regression. We used Cox Proportional Hazards models to examine associations of PA with BCa recurrence, BCa progression (recurrence or mortality), and all-cause mortality. We applied Multiple Imputation using Chained Equations to address missing data.
Among 4,386 BCa survivors with baseline PA data, 79% of non-Hispanic White (NHW), 73% Asian American (AA), 73% Hispanic, and 70% non-Hispanic Black (NHB) patients met the WHO PA guideline. The median PA level was 23 MET-hrs/wk among NHW, 18 MET-hrs/wk among AA, 17 MET-hrs/wk among Hispanic, and 14 MET-hrs/wk among NHB patients. Across race/ethnicity, meeting the WHO guideline was associated with a 22% lower rate [Adj. HR= 0.78 (0.68, 0.90)] of all-cause mortality and a 15% lower rate of BCa progression [Adj. HR= 0.85 (0.75, 0.96)] compared to not meeting the guideline. We found no statistically significant associations between PA and BCa recurrence.
These findings support promotion of guideline-level PA among breast cancer survivors and highlight the need to address barriers to physical activity among racially and ethnically minoritized groups of breast cancer survivors.