547 - EVALUATION OF PATHOLOGIC COMPLETE RESPONSE, DISEASE-FREE SURVIVAL, AND GLOBAL SURVIVAL OF PATIENTS WITH BREAST CANCER, TRIPLE-NEGATIVE SUBTYPE, WHO UNDERWENT PLATINUM-BASED NEOADJUVANT CHEMOTHERAPY AT HOSPITAL DE CÂNCER DE PERNAMBUCO IN 2018–2021

Abstract

Introduction: Neoadjuvant chemotherapy (NEO CT) plays an important role in the treatment of breast cancer. The main objective of this treatment was to provide better surgical results for patients who were initially considered unresectable or to
enable the performance of conservative surgeries for operable patients who, due to tumor size, would be candidates for
mastectomy. Besides, NEO therapy works as an in vivo sensitivity test for the applied therapy. Meta-analyses have assessed
the role of pathologic complete response (pCR; ypT0/is ypN0) in relation to global survival (GS) and disease-free survival
(DFS), with significantly favorable results. Objective: The aim of this study was to assess the pCR in patients with invasive breast cancer, triple-negative (TN) subtype, who underwent platinum-based NEO CT, in order to design a profile of
these patients, besides assessing the DFS rate and GS rate. Method: For the description of the study population, the absolute and percentage frequency distribution was represented by mean and standard deviation when the variable presented
normal distribution, and by median and interquartile interval. The applied normality test was Kolmogorov-Smirnov. The
Kaplan-Meyer graph was used to analyze GS and DFS, in order to describe the survival curves. In the comparison of survival curves, according to the condition of pCR, the log-rank test was used. The analysis was conducted using the STATA
software version 14.0. Results: The study was composed of 112 female patients with TN breast cancer who underwent
platinum-based NEO CT, with mean age of 44.5 years; 56.2% were aged between 40 and 59 years. Most patients (96.4%)
had invasive carcinoma of no special type; 54.5% at histological grade III. As for clinical staging, 33.9% were IIB, whereas
25.0% and 27.7% were IIIA and IIIB, respectively. In all, 92.0% of the patients underwent mastectomy. Almost all patients
underwent radiotherapy after surgery (111/112). Only two patients presented with disease progression during CT; 57.1%
had pCR; and 44.1% had partial response after NEO CT. Among women with complete response, DFS was 100% in 12
months, and 88.9% in 24 months, whereas for those who did not present pCR, the probability of DFS was 91.30% in 12
months and 78.02% in 24 months. Due to the small number of patients, we could not correlate the pCR rate with DFS and
GS. Conclusion: In line with the European meta-analysis published in 2018 (ESMO), our study showed high rates of pCR
after platinum-based NEO CT in patients with TN breast cancer. Contrary to data from other studies, this research could
not associate pCR with improved DFS and GS.