Abstract P6-03-06: Determining prognostic factors and optimal surgical intervention for young patients with triple-negative breast cancer
Authors: Zheng Yi-Zi , Liu Yan , Deng Zhen-Han , Liu Guo-Wen , Xie Ni 
Published: March 2023

Abstract
Background Triple-negative breast cancer (TNBC) is more frequently diagnosed in young patients, with an incidence of 26% of this population compared to 12% overall, and is characterized by high malignancy and poor prognosis. Limited data are available that contribute to a comprehensive summarization of the prognostic factors and the determination of surgical strategy that are associated with young patients with TNBC. We aimed to determine the optimal surgical approach (breast-conserving versus mastectomy) for patients aged &lt; 40 years with TNBC and establish a prognostic model. Methods We performed a cohort study with a median follow-up of 31 months using the Surveillance, Epidemiology, and End Results (SEER) data of young patients &lt; 40 years diagnosed with stage I–III TNBC between 2010 and 2016. A Cox proportional hazards model was used to investigate the effects of baseline characteristics on breast cancer-specific survival (BCSS) and overall survival (OS). To ensure that differences in outcomes were not based on baseline differences in demographic and clinical characteristics, we performed Kaplan–Meier analysis before and after propensity score matching (1:1). Subgroup analyses stratified by TNM stage as well as further propensity score matching analyses were performed. A nomogram was constructed from the multivariate logistic regression to incorporate all the prognostic factors to predict the BCSS rates of patients at 3 years and 5 years. Young patients &lt; 40 years diagnosed with stage I–III TNBC between 2006 and 2016 in Shenzhen Second People’s Hospital (SSPH) were enrolled as external validation. Results A total of 2,854 patients from SEER dataset and 250 from SSPH were included in this study. On multivariable analysis, unmarried status, lack of health insurance, advanced T stage, advanced N stage, invasive lobular carcinoma or mixed histologic type, were all significantly associated with poor BCSS and OS. Young patients with TNBC were more likely to undergo mastectomy than breast-conserving surgery. Notably, patients with T1N0M0 or T2-4N+M0 tumors who underwent breast-conserving surgery achieved longer BCSS and OS than those who underwent mastectomy; however, the type of surgery did not influence survival rates among patients with T1N+M0 or T2-4N0M0 tumors. The nomogram was constructed by the five variables and passed the calibration and validation steps (C-index: 0.774 for training cohort and 0.768 for validation cohort). The area under the receiver operating characteristic curves (AUCs) predicting the 3-year and 5-year BCSS rates were calculated (0.783 and 0.774 in training cohort; 0.786 and 0.772 in validating cohort). Conclusions A localized surgical approach may be a superior option for young patients with TNBC, especially those with T1N0M0 and T2-4N+M0 tumors. Marital status, health insurance status, T stage, N stage, and histological type were independent prognostic factors, and a nomogram established based on these variables successfully predicted the 3- and 5-year survival probabilities among these patients.
Citation Format: Yi-Zi Zheng, Yan Liu, Zhen-Han Deng, Guo-Wen Liu, Ni Xie. Determining prognostic factors and optimal surgical intervention for young patients with triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-03-06.