Recreational Physical Activity and Outcomes after Breast Cancer in Women at High Familial Risk
Menée à partir de données portant sur 4 610 patientes présentant un risque familial élevé de cancer (antécédents familiaux de cancer, présence de mutations au niveau des gènes BRCA) et atteintes d'un premier cancer invasif du sein diagnostiqué entre 1993 et 2011, cette étude analyse l'association entre la pratique d'une activité physique de loisir et la mortalité toutes causes confondues ainsi que le risque de nouveau cancer ou de récidive (1 212 décès ; 473 seconds cancers ou récidive)
Résumé en anglais
Background : Recreational physical activity (RPA) is associated with improved survival after breast cancer (BC) in average-risk women, but evidence is limited for women who are at increased familial risk because of a BC family history or BRCA1 and BRCA2 pathogenic variants (BRCA1/2 PVs).
Methods : We estimated associations of RPA (self-reported average hours-per-week within 3 years of BC diagnosis) with all-cause mortality and second BC events (recurrence or new primary) after first invasive BC in women in the Prospective Family Study Cohort (N = 4,610, diagnosed 1993–2011, 22–79 years at diagnosis). We fitted Cox proportional hazards regression models adjusted for age at diagnosis, demographics, and lifestyle factors. We tested for multiplicative interactions (Wald test statistic for cross-product terms) and additive interactions (relative excess risk due to interaction) by age at diagnosis, body mass index, estrogen receptor status, stage at diagnosis, BRCA1/2 PVs, and familial risk score estimated from multi-generational pedigree data. Statistical tests were two-sided.
Results : We observed 1,212 deaths and 473 second BC events over a median follow-up from study enrollment of 11.0 and 10.5 years, respectively. After adjusting for covariates, RPA (any versus none) was associated with lower all-cause mortality of 16.1% (95% confidence interval [CI]=2.4% to 27.9%) overall, 11.8% (95% CI=-3.6% to 24.9%) in women without BRCA1/2 PVs, and 47.5% (95% CI = 17.4% to 66.6%) in women with BRCA1/2 PVs (RPA*BRCA1/2 multiplicative interaction P = .005; relative excess risk due to interaction = 0.87, 95% CI = 0.01 to 1.74). RPA was not associated with risk of second BC events.
Conclusion : Findings support that RPA is associated with lower all-cause mortality in women with BC, particularly in women with BRCA1/2 PVs.
