Pembrolizumab combined with neoadjuvant chemotherapy is the standard of care for stage II-III triple-negative breast cancer (TNBC) based on the KEYNOTE-522 trial. However, 13 % of patients experienced immune-related adverse events (irAEs) of grade ≥3 in the trial. This study aims to describe patterns of irAEs in a real-world scenario during treatment with pembrolizumab for early-stage TNBC. Patients treated with neoadjuvant pembrolizumab plus chemotherapy across ten Brazilian cancer centers were evaluated in the Neo-Real/GBECAM0123 study. This analysis focuses on irAE evaluation, including time to onset, management, and association between irAEs and pathological complete response (pCR). A total of 368 patients were included. Overall, 31 % of patients (n = 114) presented with any grade irAEs. Most of irAEs (72.8 %) occurred during the neoadjuvant phase while 28.1 % happened during the adjuvant period. The most frequent irAEs were endocrine (12.8 % of the entire cohort), cutaneous (7.6 %) and gastrointestinal (7.1 %). A total of 50 patients (13.6 %) experienced grade ≥3 irAEs, predominantly gastrointestinal (32 %). 58 patients (56 %) needed corticosteroids. Immunotherapy rechallenge was possible in 53 % of the cases; permanent discontinuation of pembrolizumab was necessary for 16 %. No significant association was observed between irAEs and clinic-pathologic features nor pCR status. In this real-world analysis, we observed a similar incidence of irAEs as reported in the KEYNOTE-522 trial. Most patients experienced resolution of their irAEs, but some required permanent discontinuation of pembrolizumab. Additionally, there were lasting dysfunctions, particularly endocrine, demanding lifelong support. Careful monitoring and management of these events are essential.

The implementation of screening mammography has significantly altered the size distribution of breast tumors, with approximately 20% of newly diagnosed breast cancers measuring 10 mm or smaller with node-negative disease (T1aN0 and T1bN0). The management of these early-stage breast cancers remains a subject of debate. Historically, patients with T1aN0 and T1bN0 breast cancer have been excluded from adjuvant chemotherapy trials due to their excellent prognosis, with reported 10-year disease-specific survival rates exceeding 90%. However, the optimal treatment strategy for this subgroup of patients continues to be controversial, as the potential benefits of adjuvant chemotherapy must be carefully weighed against the risks of overtreatment. In this review, we summarize current evidence on outcomes and treatment strategies, highlight gaps in the literature, and provide future perspectives on the management of T1aN0 and T1bN0 breast cancer, according to immunohistochemical subtypes.

PD-1 or PD-L1 inhibitors in addition to first-line chemotherapy for endometrial cancer: an extracted individual patient data meta-analysis Mariana Carvalho