Abstract PS6-37: Clinical stage is the only predictor of survival in breast cancer patients with a complete pathological response

Abstract

Abstract INTRODUCTION In breast cancer (BC) patients, achieving a complete pathological response (pCR) after neoadjuvant chemotherapy (NCT) is associated with better prognosis. Despite this, some of these patients will experience recurrences of the disease and will eventually die of BC. We identified clinical factors that can affect recurrence and survival in BC patients who achieve pCR.METHODSRetrospective analysis of a Chilean BC database including patients treated in public and private hospitals in Santiago, Chile from 2010 to 2019. pCR was defined as the absence of residual invasive disease in the breast and in the axillary lymph nodes (ypT0/is N0) at the completion of the NCT. Invasive Disease-Free Survival (IDFS), Distant Disease-Free Survival (DDFS) and BC-specific survival (BCS) was measured from the time of diagnosis to the event or lost to follow-up. We performed Cox regression analysis to identify factors associated with prognosis.RESULTSFrom 855 patients who received NCT, 195 (22.8%) achieved pCR and were included in this study. Clinical characteristics are shown in table 1. 76 (37.9%) patients had hormone receptor positive (HR+) and 113 (57.4%) had Human epidermal growth factor 2 (HER2) positive tumors. 88.7% were treated with a regimen that included anthracyclines and taxanes. With a median follow-up of 36 months, three-year IDFS, DDFS and BCS and their 95% confidence intervals were 90.9% (84.7 - 94.6), 91.8% (86.0 - 95.3) and 93.8% (87.8 - 97.5); respectively. The stage at diagnosis was the only predictor associated with IDFS (Hazard ratio (HR) = 5.6; p = 0.02), DDFS (HR = 4.1, p = 0.07), and BCS (HR = 8.3, p = 0.04). Body mass index (BMI), age, hospital, HR or HER2 status, lymph node involvement, or the presence of an in-situ component, were not associated with prognosis in the multivariate analysis.CONCLUSIONThe clinical stage at diagnosis was the only predictor of survival in patients who achieved pCR after NCT. Short follow-up and few events may have affected these results. This data is consistent with previously published work. Table 1. Tumor and patient characteristicsMedian age49 (24 – 78)HospitalPublic57.4%Private43.6%BMIMedian27.2 (18.5 – 44.7)Overweight38.0%Obese31.9%Receptor StatusRH+/HER2-16.4%RH+/HER2+21.5%RH-/HER2+35.9%RH-/HER2-26.2%Clinical StageI2.1%II47.4%III50.5%Lymph Node +69.7%ypT0/N078.1%ChemotherapyAnthracycline5.1%Taxane6.2%Anthracycline-Taxane88.7% Citation Format: Francisco Acevedo, Benjamin Walbaum, Tomas Merino, Militza Petric, Cesar Sanchez. Clinical stage is the only predictor of survival in breast cancer patients with a complete pathological response [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS6-37.