Early first-line systemic anticancer therapeutic attrition after metastatic recurrence in triple-negative breast...

To assess the incidence and determinants of early first-line systemic anticancer therapeutic attrition after metastatic recurrence in triple-negative breast cancer (TNBC) treated with neoadjuvant chemo-immunotherapy.

We conducted a retrospective multicenter analysis of 209 consecutive patients with early-stage TNBC treated with neoadjuvant chemo-immunotherapy. After a median follow-up of 24 months, 54 developed metastatic recurrence. Early first-line systemic anticancer therapeutic attrition was defined as failure to initiate systemic anticancer therapy within 90 days of documented recurrence. Associations were evaluated using univariate and multivariable logistic regression.

Among patients who developed metastatic recurrence, 17 of 54 evaluable patients (32.7%) experienced early first-line systemic anticancer therapeutic attrition. Patients who did not initiate treatment had a significantly shorter disease-free interval compared with those who received first-line therapy (median 7.4 vs. 14.3 months; p = 0.011). PD-L1 positivity was more frequent in the attrition group (64.7% vs. 28.6%; p = 0.021), and central nervous system metastases were more commonly observed (41.2% vs. 20.0%). Median overall survival from metastatic recurrence was 3.4 months in the attrition group compared with 12.4 months in the no-attrition group. In multivariable analysis, shorter disease-free interval (OR 0.87 per month; 95% CI 0.78-0.97), PD-L1 positivity (OR 8.73; 95% CI 1.81-42.04), and presence of central nervous system metastases (OR 7.09; 95% CI 1.41-35.57) were independently associated with early first-line therapeutic attrition.

In this real-world multicenter cohort, nearly one-third of patients with TNBC experiencing metastatic recurrence after neoadjuvant chemo-immunotherapy did not initiate first-line systemic therapy within a clinically relevant timeframe. Early first-line systemic anticancer therapeutic attrition represents a meaningful gap in the care continuum and warrants improved surveillance and multidisciplinary management strategies.

Not applicable.