Introduction: Triple-negative breast cancer (TNBC) is notably an aggressive breast cancer (BC) subtype, leading to early relapse and poor prognosis. Effects of adjuvant chemotherapy among early-stage TNBC (pT1N0M0) patients remain unclear in different populations. Objectives: Our study aimed to determine the impact of adjuvant chemotherapy on overall survival (OS) and progression-free survival (PFS) within the specific subset of Peruvian pT1N0M0 TNBC patients (pT1a/b vs. pT1c). Methods: We retrospectively analyzed 2007 TNBC cases diagnosed between 2000-2014 at the Instituto Nacional de Enfermedades Neoplásicas (Lima, Peru). We included only non-metastatic TNBC cases and classified them as pT1N0M0 after surgery. TNBC patients who underwent neoadjuvant chemotherapy were excluded. We describe our population according to the tumor size from the residue disease (pT1a/b vs. pT1c). We used the...