Incidence and outcome of brain and/or leptomeningeal metastases in HER2-low metastatic breast cancer in the French ESME cohort.

BACKGROUND: Breast cancer (BC) is the second most common cancer that metastasizes to the brain. Particularly up to half of patients with human epidermal growth factor receptor 2 (HER2)-positive (HER2+) metastatic breast cancer (mBC) may develop brain metastases over the course of the disease. Nevertheless, little is known about the prevalence and the outcome of brain and leptomeningeal metastases (BLMM) in HER2-low BC. We compared the cumulative incidence of BLMM and associated outcomes among patients with HER2-low, HER2-negative (HER2-) and HER2+ mBC. PATIENTS AND METHODS: This cohort study was conducted from the Epidemiological Strategy and Medical Economics (ESME) mBC database and included patients treated for mBC between 2012 and 2020 across 18 French comprehensive cancer centers and with known HER2 and hormone receptor (HR) status. The cumulative incidence of BLMM after metastatic diagnosis was estimated using a competing risk methodology with death defined as a competing event. RESULTS: 19 585 patients were included with 6118 (31.2%), 9943 (50.8%) and 3524 (18.0%) being HER2-low, HER2- and HER2+ mBC, respectively. After a median follow-up of 48.6 months [95% confidence interval (CI) 47.7-49.3 months], BLMM were reported in 4727 patients: 1192 (25.2%) were diagnosed with BLMM at first metastatic diagnosis and 3535 (74.8%) after metastatic diagnosis. Multivariable analysis adjusted for age, histological grade, metastases-free interval and HR status showed that the risk of BLMM at metastatic diagnosis was similar in patients with HER2- compared to HER2-low mBC [odds ratio (OR) (95% CI) 1.00 (0.86-1.17)] and higher in those with HER2+ compared to HER2-low [OR (95% CI) 2.23 (1.87-2.66)]. Similar results were found after metastatic diagnosis; the risk of BLMM was similar in HER2- compared to HER2-low [subdistribution hazard ratio (sHR) (95% CI) 1.07 (0.98-1.16)] and higher in the HER2+ group [sHR (95% CI) 1.56 (1.41-1.73)]. CONCLUSIONS: The prevalence and evolution of BLMM in HER2-low mBC are similar to those in patients with HER2- tumors. In contrast to patients with HER2+ mBC, the prognosis of BLMM remains dismal in this population.

Enrollment of older metastatic breast cancer patients in first-line clinical trials: 9-year experience of the large-scale real-life multicenter French ESME cohort.

PURPOSE: Older cancer patients are underrepresented in clinical trials. We aimed to evaluate the enrollment of older women aged 70 years old (yo) or over with metastatic breast cancer (MBC) in clinical trials. METHODS: We used the national Epidemio-Strategy and Medical Economics MBC Data Platform, a French multi-center real-life database. We selected MBC women over 70yo, without central nervous system metastases, with at least one line of systemic treatment, between January 1st, 2008 and December 31st, 2016, and had no other cancer in the 5 years before MBC. The primary objective was to evaluate the proportion of patients enrolled in clinical trials according to their age. Secondary objective was to identify variables associated with enrollment in older ones. RESULTS: 5552 women were aged ≥ 70 (median 74yo; IQR 72-77). 14,611 were less than 70. Of the older ones, 239 (4%) were enrolled in a clinical trial during first line of treatment, compared with 1529 (10.5%) for younger ones. Multivariable analysis of variables predicting for enrollment during first line of treatment in older patients were younger age (OR 0.50 [95%CI 0.33-0.76] for the 80-85yo class; OR 0.17 [95%CI 0.06-0.39] for the 85yo and more class), good ECOG Performance Status (PS 0-1) (OR 0.15 [95%CI 0.08-0.27] for the PS 2-4 class), HER2 + disease (OR 1.78 [95%CI 1.27-2.48]), type of treatment (chemotherapy/targeted therapy/immunotherapy OR 5.01 [95%CI 3.13-8.18]), and period (OR 1.65 [95%CI 1.22-2.26] for 2012-2016, compared to 2008-2011). CONCLUSION: In this large database, few older MBC patients were enrolled in a trial compared with younger ones.