Neoadjuvant versus adjuvant chemotherapy in luminal B-like breast cancer: a subset analysis of the CANTO study

Background

The benefit of neoadjuvant chemotherapy (NAC) in hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer (BC) remains uncertain, given low pathologically documented complete response (pCR) rates and limited long-term comparative data. We compared overall survival (OS) between NAC and adjuvant chemotherapy (AC) in luminal B-like breast cancer treated in routine practice. Patients and methods: Patients enrolled in the prospective French CANTO cohort between January 2012 and December 2018 with unilateral, nonmetastatic, grade 3 HR-positive/HER2-negative BC (cT2-T3N0-N3M0) treated with NAC followed by surgery or with primary surgery followed by AC were included. The primary endpoint was OS; secondary endpoints were distant recurrence-free survival (DRFS) and invasive disease-free survival; exploratory endpoints were BC-specific survival, locoregional recurrence-free survival (LRFS) and breast recurrence-free survival. Inverse probability of treatment weighting (IPTW) was applied, with weighted Kaplan-Meier estimates and Cox models.