Risk-Adapted Postmastectomy Radiotherapy Decision Based on Prognostic Nomogram for pT1-2N1M0 Breast Cancer: A Multicenter Study

Ming Li; Jinbo Yue; Xiangbo Wan; Bin Hua; Qiuan Yang; Pei Yang; Zijian Zhang; Qian Pei; Weidong Han; Yaping Xu; Xuefeng Xia

doi:10.3389/fonc.2020.588859

Risk-Adapted Postmastectomy Radiotherapy Decision Based on Prognostic Nomogram for pT1-2N1M0 Breast Cancer: A Multicenter Study

Front Oncol. 2020 Dec 11:10:588859. doi: 10.3389/fonc.2020.588859. eCollection 2020.

Authors

Ming Li¹, Jinbo Yue², Xiangbo Wan³, Bin Hua⁴, Qiuan Yang⁵, Pei Yang⁶, Zijian Zhang⁷, Qian Pei⁸, Weidong Han⁹, Yaping Xu¹⁰, Xuefeng Xia¹⁰

Affiliations

¹ Department of Radiation Oncology, Beijing Hospital/National Center of Gerontology, Beijing, China.
² Department of Radiation Oncology, Shandong Cancer Hospital Affiliated to Shandong University/Shandong Academy of Medical Sciences, Jinan, China.
³ Department of Radiation Oncology, The Sixth Affiliated Hospital - Sun Yat-sen University, Guangzhou, China.
⁴ Department of Breast Cancer Surgery, Beijing Hospital/National Center of Gerontology, Beijing, China.
⁵ Department of Radiation Oncology, Qilu Hospital of Shandong University, Jinan, China.
⁶ Department of Radiation Oncology, Hunan Cancer Hospital/The Affiliated Cancer Hospital of Xiangya School of Medicine - Central South University, Changsha, China.
⁷ Department of Radiation Oncology, Xiangya Hospital - Central South University, Changsha, China.
⁸ Department of General Surgery, Xiangya Hospital - Central South University, Changsha, China.
⁹ Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
¹⁰ Geneplus-Beijing Institute, Beijing, China.

Abstract

Purpose: The aim of this study was to develop a widely accepted prognostic nomogram and establish a risk-adapted PMRT strategy based on locoregional recurrence for pT1-2N1M0 breast cancer.

Methods and materials: A total of 3,033 patients with pT1-2N1M0 breast cancer treated at 6 participating institutions between 2000 and 2016 were retrospectively reviewed. A nomogram was developed to predicted locoregional recurrence-free survival (LRFS). A propensity score-matched (PSM) analyses was performed in risk-adapted model.

Results: With the median follow-up of 65.0 months, the 5-year overall survival (OS), disease free survival (DFS) and LRFS were 93.0, 84.8, and 93.6%, respectively. There was no significant difference between patients who received PMRT or not for the entire group. A nomogram was developed and validated to estimate the probability of 5-year LRFS based on five independent factors including age, primary tumor site, positive lymph nodes number, pathological T stage, and molecular subtype that were selected by a multivariate analysis of patients who did not receive PMRT in the primary cohort. According to the total nomogram risk scores, the entire patients were classified into low- (40.0%), moderate- (42.4%), and high-risk group (17.6%). The 5-year outcomes were significantly different among these three groups (P<0.001). In low-risk group, patients who received PMRT or not both achieved a favorable OS, DFS, and LRFS. In moderate-risk group, no differences in OS, DFS, and LRFS were observed between PMRT and no PMRT patients. In high-risk group, compared with no PMRT, PMRT resulted in significantly different OS (86.8 vs 83.9%, P = 0.050), DFS (77.2 vs 70.9%, P = 0.049), and LRFS (90.8 vs. 81.6%, P = 0.003). After PSM adjustment, there were no significant differences in OS, DFS, and LRFS in low-risk and moderate-risk groups. However, in the high-risk group, PMRT still resulted in significantly better OS, DFS and improved LRFS.

Conclusions: The proposed nomogram provides an individualized risk estimate of LRFS in patients with pT1-2N1M0 breast cancer. Risk-adapted PMRT for high-risk patients is a viable effective strategy.

Keywords: breast neoplasms; mastectomy; molecular subtype; nomogram; prognosis; radiation therapy; recurrence; risk-adapted therapy.