Time trends of overall survival among metastatic breast cancer patients in the real-life ESME cohort

Aim Real-life analysis of overall survival (OS) trends among metastatic breast cancer (MBC) patients may help define medical needs and evaluate the impact of public health investments. The present study aimed to evaluate the independent impact of the year of MBC diagnosis on OS in the Epidemio-Strategy-Medical-Economical (ESME)-MBC cohort. Methods ESME-MBC (NCT03275311) is a French, national, multicentre, observational cohort including 16,702 consecutive newly diagnosed MBC patients (01 January 2008–31 December 2014). Of 16,680 eligible patients, 15,085 had full immunohistochemistry data, allowing classification as hormone receptor–positive and HER2-negative (HR+/HER2–, N = 9907), HER2-positive (HER2+, N = 2861) or triple-negative (HR–/HER2–, N = 2317) subcohorts. Multivariate analyses of OS were conducted among the full ESME cohort and subcohorts. Results Median OS of the whole cohort was 37.22 months (95% confidence interval [CI], 36.3–38.04). Year of diagnosis was an independent predictor of OS (hazard ratio 0.98 [95% CI, 0.97–1.00], P = .01) together with age, subtype, disease-free interval, visceral metastases and number of organs involved. Median OS of HR+/HER2–, HER2+ and HR–/HER2– subcohorts was, respectively, 42.12 (95% CI, 40.90–43.10), 44.91 (95% CI, 42.51–47.90) and 14.52 (95% CI, 13.70–15.24) months. Year of diagnosis was a strong independent predictor of OS in HER2+ subcohort (hazard ratio 0.91 [95% CI, 0.88–0.94], P < .001), but not in HR+/HER2– nor HR–/HER2– subcohorts (hazard ratio 1.00 [95% CI, 0.98–1.01], P = .80 and 1.00 [95% CI, 0.97–1.02], P = .90, respectively). Conclusions The OS of MBC patients has slightly improved over the past decade. However, this effect is confined to HER2+ cases, highlighting the need of new strategies in the other subtypes.