Reduction of Neoadjuvant Treatment in Early Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer. The KEYNOTE-522 trial established neoadjuvant chemotherapy combined with pembrolizumab as a standard treatment for patients with stage II-III TNBC, resulting in improved pathological complete response rates and survival outcomes. However, this treatment approach is associated with substantial toxicity, which may lead to treatment discontinuation and long-term adverse effects. Patients who achieve a pathological complete response have an excellent prognosis, supporting the development of treatment de-escalation strategies. High levels of tumor-infiltrating lymphocytes (TILs) are associated with increased response rates and favorable outcomes in TNBC. This multicenter, prospective, phase II, non-comparative study aims to evaluate a de-escalated neoadjuvant treatment strategy in patients with stage II TNBC and TILs ≥30%. Participants will receive 12 weeks of neoadjuvant treatment with carboplatin, paclitaxel, and pembrolizumab. The primary objective is to evaluate the proportion of patients with no suspected residual tumor on breast MRI and biopsy after 12 weeks of treatment, confirmed by pathological examination at surgery. Secondary objectives include evaluation of event-free survival, overall survival, residual cancer burden, safety, quality of life, fear of cancer recurrence, and the association between imaging findings, TIL levels, and treatment response. Exploratory analyses will investigate potential circulating and tissue biomarkers associated with treatment efficacy.