Evaluation of the Pathological Complete Response (pCR) as a Surrogate Endpoint of Neoadjuvant Chemotherapy: Real-World Evidence

Abstract

Abstract Purpose Neoadjuvant chemotherapy (NAC), which in the past was only used only in for locally advanced disease, is currently being used upfront, especially in to treat aggressive breast cancer (BC). Real-world data (RWD) can address important research questions based on daily routine daily cancer care. The objective of this study was to characterize the pathological complete response (pCR) and its relationship with overall survival (OS) and disease-free survival (DFS) in BC patients with BC who received NAC at a Brazilian public reference center, a. And also to characterize the relationship between pCR and the BC subtypes, of BC and DFS and OS. Methods This was a retrospective cohort study based on a large BC database from a women’s health reference center for women’s health in Brazil. Patients with BC diagnosed between 2011 and 2020 were included if they received NAC. Data on regarding demographics, cancer-related information, treatment-related information, pCR, OS and DFS were collected. Survival analyses were performed using the semiparametric Kaplan‒Meier method to assess OS and DFS by using pCR status, considering BC diagnosis as the index date. Results A total of 1601 patients were included. BC patients were on average 49 years old and presented with stage IIIa disease (35%). Most patients had invasive nonspecial- type (NST) disease (94%);, and 86.7% of patients had a the Ki-67 index was ≥ 14 in 86.7% of patients. The overall pCR rate was 22.7%;, and pCR was observed more frequently in triple-negative and luminal B subtypes. A significant proportion of pCR patients were alive (89% vs. 61%, log-rank p < 0.0001) and had a greater DFS status (90% vs. 66%, log-rank p < 0.0001). Only Luminal A patients did not have a association of better worse OS and DFS associated with pCR. Conclusions Updated real-world data on for BC patients who received NAC in this Brazilian cohort have showedn that a 22.7%the pCR rate was 22.7% for all cancer subtypes and stages. Only Luminal A patients’ pCR status was not didn’t have associatedion of with a better OS and or DFS with pCR.