Immune-related adverse events as predictors of pathological complete response in early-stage triple-negative breast cancer treated with pembrolizumab

Abstract

PurposeNeoadjuvant chemoimmunotherapy improved pathological complete response (pCR) rates in early triple-negative breast cancer (TNBC). However, the relationship between immune-related adverse events (irAEs) and treatment response remains unclear. This study evaluated the association between the development of irAEs and pCR in TNBC patients receiving neoadjuvant pembrolizumab-based therapy.MethodIn this multicenter retrospective study, early TNBC patients who received neoadjuvant pembrolizumab-based therapy were evaluated. Clinicopathologic features, irAE occurrence, and pCR rates were recorded and analyzed.ResultsAmong 203 patients who completed neoadjuvant treatment and underwent surgery, 127 (62.6%) achieved pCR. irAEs were more frequent in the pCR group compared with the non-pCR group (35.4% vs 19.7%, respectively; p = 0.01). Both univariate and multivariate analyses confirmed a significant association between irAE development and pCR.ConclusionIn patients with early TNBC treated with neoadjuvant pembrolizumab, irAEs occurred more often in those achieving pCR. These findings suggest that irAEs may reflect enhanced immune activation and could serve as a potential indicator of treatment response. Further prospective studies are needed to validate this observation and clarify its clinical relevance.