Influence of age as a continuous variable on the prognosis of patients with pT1-2N1 breast cancer

作者：Zhao, Xu-Ran; Tang, Yu; Wu, Hong-Fen; Guo, Qi-Shuai; Zhang, Yu-Jing; Shi, Mei; Cheng, Jing; Wang, Hong-Mei; Liu, Min; Ma, Chang-Ying; Wen, Ge; Wang, Xiao-Hu; Fang, Hui; Jing, Hao; Song, Yong-Wen; Jin, Jing; Liu, Yue-Ping; Chen, Bo; Qi, Shu-Nan; Li, Ning; Tang, Yuan; Lu, Ning-Ning; Zhang, Na^*; Li, Ye-Xiong^*; Wang, Shu-Lian^*

来源：BREAST, 2022, 66: 136-144.

DOI：10.1016/j.breast.2022.08.005

• Breast neoplasm
• Age
• Mastectomy
• Radiotherapy
• 1-3 positive lymph nodes

Purpose: To assess the influence of age as a continuous variable on the prognosis of pT1-2N1 breast cancer and examine its decision-making value for postmastectomy radiotherapy (PMRT). Methods: We retrospectively evaluated 5438 patients with pT1-2N1 breast cancer after mastectomy in 11 hospitals. A multivariable Cox proportional hazards regression model with penalized splines was used to examine the relationship between age and oncologic outcomes. Results: The median follow-up was 67.0 months. After adjustments for confounding characteristics, nonsignificant downward trend in locoregional recurrence (LRR) risk was observed with increasing age (P-non-linear association = 0.640; P-linear association = 0.078). A significant non-linear association was found between age and disease-free survival (DFS) and overall survival (OS) (P-non-linear association <0.05; P-linear association >0.05, respectively). The DFS and OS exhibited U-shaped relationships, with the hazard ratios (HRs), reaching a nadir at 50 years old. A decreased risk of LRR with PMRT vs. no PMRT (HR = 0.304, 95% CI: 0.204-0.454) was maintained in all ages. The HR of PMRT vs. no PMRT for DFS and OS gradually increased with age. In patients <= 50 years old, PMRT was independently associated with favorable LRR, DFS, and OS, all P < 0.05). In patients >50 years old, PMRT was independently associated with reduced LRR (P = 0.004), but had no effect on DFS or OS. Conclusions: Age was an independent prognostic factor for pT1-2N1 breast cancer; PMRT provided survival benefits for patients <= 50 years old, but not for patients >50 years old.

• 单位
  重庆大学; 中国医学科学院; 广州医学院; 南方医科大学; 华中科技大学; 中国人民解放军第四军医大学; 吉林大学; 中国医学科学院北京协和医院; 中山大学