21-gene recurrence score in predicting the outcome of postoperative radiotherapy in T1-2N1 luminal breast cancer after breast-conserving surgery

• Published in: Breast (Edinburgh) 2024-04, Vol.74, p.103679-103679, Article 103679
• Main Authors: Xie, Shang-Jin, Wang, Run-Jie, Wu, San-Gang, Zhang, Fu-Xing
• Format: Article
• Language: English
• Subjects: Breast cancer; Breast Neoplasms - genetics; Breast Neoplasms - radiotherapy; Breast Neoplasms - surgery; Chemotherapy, Adjuvant; Female; Humans; Mastectomy, Segmental; Neoplasm Staging; Original; Postoperative radiotherapy; Propensity score matching; Recurrence score; Survival
• ISSN: 0960-9776; 1532-3080
• DOI: 10.1016/j.breast.2024.103679

In those with one to three positive lymph nodes (N1) breast cancer (BC), the 21-gene recurrence score (RS) classification can be referred for decision-making on adjuvant chemotherapy. This study aimed to investigate the effect of RS in predicting the survival benefit of postoperative radiotherapy (PORT) in T1-2N1 BC with estrogen receptor-positive and human epidermal growth factor receptor 2-negative disease after breast-conserving surgery (BCS). We included patients with BC and available RS data from the Surveillance, Epidemiology, and End Results Oncotype DX database. The chi-square test, Kaplan-Meier method, propensity score matching (PSM) as well as multivariable Cox proportional hazard analyses were used for statistical analyses. We included 6509 patients in the analysis. Of these patients, 5302 (85.5%) were treated with BCS + PORT, and 207 (15.5%) had BCS alone. There were 1419 (21.8%), 4319 (66.4%), and 771 (11.8%) patients being low-, intermediate-, and high-risk RS, respectively. After PSM, PORT was significantly associated with a 5-year overall survival (OS) advantage (95.1% vs. 90.5%, P