Aim: To describe first-line treatments, overall (OS) and real-world progression-free (rwPFS) survival in women with hormone receptor-positive, HER2-negative (HR+/HER2-) metastatic breast cancer (mBC) following introduction of CDK4/6 inhibitors (CDK4/6i), according to age (<70; 70 +) and diagnostic period (before/after CDK4/6i).
Methods: We extracted data from the ESME database (NCT03275311) which includes consecutive patients starting first-line mBC in one of the 18 French Comprehensive cancer centres.
Results: We identified 17,830 eligible women (median age: 62 years). Women aged ≥ 70 years were less likely to present with aggressive disease characteristics. Use of endocrine therapy combined with CDK4/6i increased substantially over time in both age groups, from 0.9 % to 48.9 % in 70 + women, and from 0.8 % to 50.1 % in women < 70 (p < 0.001 for both). In contrast, first-line chemotherapy (alone or in combination) declined from 52.7 % to 30.0 % (p < 0.001), with consistently lower use among women 70 + compared to those < 70: 32.2 % vs. 61.1 % prior to 2016, and 16.4 % vs. 36.5 % after 2017 (p < 0.001 for both). Among 70 + women, OS improved over time (34.0-37.3 months, p = 0.03) but remained shorter than in younger women. rwPFS improved in both age groups: from 12.6 to 14.8 months in 70 + women, and from 12.3 to 14.4 months in women < 70 (p < 0.001 for both).
Conclusion: ET+CDK4/6i use rose up to ∼50 % after 2017, reaching ∼70 % in recent years among women with good PS, but remained ∼50 % in older patients with poor PS. Broader adoption is needed, with less chemotherapy use. Survival outcomes have improved but, causality cannot be confirmed due to the observational design.
Keywords: HER2-; Metastatic breast cancer; Older patients; Positive hormone receptors; Real-word data; Survival endpoints.
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