Association of chemotherapy and comorbidities with overall survival in elderly patients with early breast cancer: a French population-based propensity score-matched analysis.

BACKGROUND: Additional systemic treatment for early breast cancer in elderly is challenged by increasing comorbidities with age. We aimed to examine the effect of additional chemotherapy on overall survival in patients aged 70 years or older and the impact of comorbidities on chemotherapy benefit. METHODS: This retrospective monocentric cohort study includes data from all patients aged 70 years and older who underwent surgery for an early breast cancer from 1997 to 2016. A propensity score analysis allowed adjustment for chemotherapy prescription preferences based on tumour characteristics. RESULTS: Of 15,599 patients who had surgery for an early breast cancer, 1743 (11.2%) over 70 years old were included, of whom 269 (15.4%) had received additional chemotherapy. Median follow-up was 5.3 years. Multivariate analyses on the propensity-score weighted cohort (n = 1 354) identified improved overall survival in patients with chemotherapy versus without (HR 0.54, 95% CI 0.31-0.92). Chronic obstructive pulmonary disease (HR, 2.16, 95% CI 1.40-3.34) and polypharmacy (HR 1.40, 95%CI 1.07-1.84) were associated with worse overall survival. No statistically significant interactions were identified between these comorbidities and chemotherapy prescription. CONCLUSION: Additional chemotherapy in elderly with early breast cancer is feasible and associated with overall survival benefit, supporting the importance of chemotherapy considerations in this population, and of avoiding undertreatment based on chronological age considerations alone.