ANALYSIS OF PATIENTS WITH LOCALLY ADVANCED BREAST CANCER TREATED AT ICESP

Abstract

Objective: The aim of this study was to assess the oncological efficacy of breast-conserving surgery (BCS) after neoadjuvant therapy (NT) in patients with invasive locally advanced breast cancer (LABC). Methodology: A retrospective cohort study was conducted at the Instituto do Cancer de São Paulo Octavio Frias de Oliveira (ICESP), with LABC (Stages IIb– III) treated with NT between 2010 and 2015. The endpoints were disease-free survival (DFS), local disease-free survival (LDFS), overall survival (OS), and residual tumor volume, considering pathological complete response (PCR) as ypT0 ypN0. The multivariable analyses were performed by using the Cox proportional hazard models. Results: In this study, 529 patients were included. The mean age was 52.7 (51.53–53.90). All patients were submitted to NT, i.e., 95.5% was submitted to neoadjuvant chemotherapy and 4.5%, hormone therapy. The mean follow-up was 62.33 (60.01–64.65) months. The PCR was identified in 12.7%. The BCS was performed in 24.6% (130) patients versus 75.4% (399) of mastectomies (MTs). There were no differences in 13% versus 9.2% (95%CI; p=0.2) LDFS for MT and BCS. The DFS was lower at 55.4% in the MT group versus 77.7% in the BCS group (95%CI; p<0.001). The mortality rate was 29.5%. In multivariable, the following factors were associated with higher risk of mortality: non-PCR (relative risk [RR] 2.23; 95%CI 1.173–4.242; p=0.002), pathological stage 3B or 3C (RR 2.193; 95%CI 1.377–3.492; p=0.004), and Ki67>30 (RR1.8; 95%CI 1.331–2.618; p=0.000). The type of surgery had no impact on mortality (RR 1.47; 95%CI 0.945–2.298; p=0.08). Conclusion: In our population, the BCS does not affect the LDFS rates and mortality, which seems to be safe to perform in patients who desire to conserve the breast after neoadjuvant treatment. PCR, clinical stage, and Ki67 had an important impact on mortality.