Neoadjuvant pembrolizumab plus chemotherapy in older patients with early-stage triple-negative breast cancer: real-world insights from neo-real/GBECAM-0123.

The KEYNOTE-522 regimen is the standard of care for stage II-III triple-negative breast cancer (TNBC). However, older patients were underrepresented in the pivotal trial. We evaluated the effectiveness and safety of this regimen in patients aged ≥65 years enrolled in the Neo-Real/GBECAM-0123 multicenter real-world study conducted across institutions in Brazil and Argentina. Among 724 patients, 80 (11%) were aged ≥65 years and presented distinct baseline characteristics, including lower frequencies of grade 3 tumors, Ki67 ≥ 50%, and germline BRCA1/2 mutations, alongside a higher prevalence of impaired performance status. The pathologic complete response (pCR) rate in older patients was 54.9% in comparison with 64.5% in younger patients, although age was not independently associated with pCR in multivariable analysis, including other relevant baseline variables. Older patients experienced a significantly higher toxicity burden, with increased rates of treatment discontinuation, dose reductions, treatment delays, hospitalizations, and grade ≥3 neutropenia. Taken together, these data indicate that older patients with TNBC harbor distinct biological and clinical features with numerically lower pCR rates, and that the increased toxicity burden underscores the need for personalized treatment strategies and dedicated research in this population.