Effect of postmastectomy radiotherapy on pT1-2N1 breast cancer patients with different molecular subtypes
Xin-Yuan Guo,
Guang-Yi Sun,
Hong-Mei Wang,
Min Liu,
Yu-Jing Zhang,
Na Zhang,
Yu Tang,
Xu-Ran Zhao,
Hao Jing,
Hui Fang,
Ge Wen,
Qi-Shuai Guo,
Hong-Fen Wu,
Xiao-Hu Wang,
Chang-Ying Ma,
Ye-Xiong Li,
Jing Cheng,
Mei Shi,
Shu-Lian Wang
Affiliations
Xin-Yuan Guo
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
Guang-Yi Sun
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
Hong-Mei Wang
Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China
Min Liu
Department of Radiation Oncology, First Hospital of Jilin University, Changchun, China
Yu-Jing Zhang
Department of Radiation Oncology, Sun Yat-sen University Affiliated Tumor Hospital, Guangzhou, China
Na Zhang
Department of Radiation Oncology, Liaoning Cancer Hospital, Shenyang, China
Yu Tang
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
Xu-Ran Zhao
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
Hao Jing
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
Hui Fang
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
Ge Wen
Department of Radiation Oncology, Sun Yat-sen University Affiliated Tumor Hospital, Guangzhou, China; Department of Radiation Oncology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
Qi-Shuai Guo
Department of Radiation Oncology, Affiliated Cancer Hospital of Chongqing University, Chongqing, China
Hong-Fen Wu
Department of Radiation Oncology, Jilin Cancer Hospital, Changchun, China
Xiao-Hu Wang
Department of Radiation Oncology, Gansu Cancer Hospital, Lanzhou, China
Chang-Ying Ma
Department of Radiation Oncology, Qiqihaer First Hospital, Qiqihaer, China
Ye-Xiong Li
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
Jing Cheng
Department of Breast Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Corresponding author.
Mei Shi
Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, China; Corresponding author.
Shu-Lian Wang
Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; Corresponding author.
Objective: To clarify the effect of postmastectomy radiotherapy (PMRT) on pT1-2N1 breast cancer patients with different molecular subtypes. Methods: We retrospectively analyzed the data of 5442 patients with pT1-2N1 breast cancer treated using modified radical mastectomy in 11 hospitals in China. Univariate, multivariate, and propensity score matching (PSM) analyses were used to evaluate the effect of PMRT on locoregional recurrence (LRR). Results: With a median follow-up duration of 63.8 months, the 5-year LRR rates were 4.0% and 7.7% among patients treated with and without PMRT, respectively (p < 0.001). PMRT was independently associated with reduced LRR after adjustments for confounders (p < 0.001). After grouping the patients according to the molecular subtype of cancer and conducting PSM, we found that the 5-year LRR rates among patients treated with and without PMRT (in that order) were as follows: luminal HER2-negative cancer, 1.9% and 6.5% (p < 0.001); luminal HER2-positive cancer, 3.8% and 13.7% (p = 0.041); HER2-overexpressing cancer, 10.2% and 15.5% (p = 0.236); and triple-negative cancer, 4.6% and 15.9% (p = 0.002). Among patients with HER2-overexpressing and triple-negative cancers, the LRR hazard rate displayed a dominant early peak, and was extremely low after 5 years. However, patients with luminal cancer continued to have a long-lasting high annual LRR hazard rate during follow-up. Conclusion: PMRT significantly reduced the LRR risk in patients with pT1-2N1 luminal and triple-negative breast cancers, but had no effect on the LRR risk in patients with HER2-overexpressing cancer. Patients with different molecular subtypes displayed different annual LRR patterns, and the late recurrence of the luminal subtype suggests the necessity of long-term follow-up to evaluate the efficacy of PMRT.
