Real-world clinical and survival outcomes of patients with early relapsed triple-negative breast cancer from the ESME national cohort.

Background: Early metastatic relapse of triple-negative breast cancer (mTNBC) after anthracyclins and/or taxanes based (A/T) primary treatment represents a highly aggressive cancer situation requiring urgent characterisation and handling. Epidemio-Strategy-Medico-Economical-Metastatic Breast Cancer (ESME-MBC) database, a multicenter, national, observational cohort (NCT03275311) provides recent data on this entity.

Methods: All ESME patients diagnosed between 2008 and 2020 with mTNBC occurring as a relapse after a systemic neoadjuvant/adjuvant taxane and/or anthracycline-based chemotherapy were included. Early relapses were defined by a metastatic diagnosis up to 12 months of the end of neo/adjuvant A/T chemotherapy. We assessed overall survival (OS) and progression-free-survival under first-line treatment (PFS1) by early versus late relapse (≥12 months).

Results: Patients with early relapse (N = 881, 46%) were younger and had a larger tumour burden at primary diagnosis than those with late relapses (N = 1045). Early relapse rates appeared stable over time. Median OS was 10.1 months (95% CI 9.3-10.9) in patients with early relapse versus 17.1 months (95% CI 15.7-18.2) in those with late relapse (adjusted hazard-ratio (aHR): 1.92 (95% CI 1.73-2.13); p < 0.001). The median PFS1 was respectively 3.1 months (95% CI 2.9-3.4) and 5.3 months (95% CI 5.1-5.8); (aHR: 1.66; [95% CI 1.50-1.83]; p < 0.001). Among early relapsed patients, a higher number of metastatic sites, visceral disease but not treatment types, were independently associated with a poorer OS.

Conclusion: These real-world data provide strong evidence on the dismal prognosis, higher treatment resistance and major unmet medical need associated with early relapsed mTNBC. Database registration: clinicaltrials.gov Identifier NCT032753.