AUTHOR=Luo Meng , Chen Huihui , Deng Hao , Jin Yao , Wang Gui , Zhang Kun , Ma Hong , Chen Yiding , Zhang Suzhan , Zhou Jiaojiao 

TITLE=Postmastectomy Radiotherapy After Neoadjuvant Chemotherapy in cT1-2N+ Breast Cancer Patients: A Single Center Experience and Review of Current Literature

JOURNAL=Frontiers in Oncology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.881047

DOI=10.3389/fonc.2022.881047

ISSN=2234-943X

ABSTRACT=<sec><title>Purpose</title><p>Postmastectomy radiotherapy (PMRT) after neoadjuvant chemotherapy (NAC) in breast cancer patients with initial clinical stage cT<sub>1-2</sub>N<sub>+</sub>, especially for those who achieved ypT<sub>1-2</sub>N<sub>0</sub>, is still controversial. This study was to evaluate the survival prognosis of cT<sub>1-2</sub>N<sub>+</sub> patients after NAC with or without PMRT, and to discuss the selection of patients who may omit PMRT.</p></sec><sec><title>Patients and Methods</title><p>From January 2005 to December 2017, 3055 female breast cancer patients underwent mastectomy in our medical center, among whom 215 patients of cT<sub>1-2</sub>N<sub>+</sub> stage, receiving NAC with or without PMRT were finally analyzed. The median follow-up duration was 72.6 months. The primary endpoint was disease-free survival (DFS), and secondary endpoint was overall survival (OS). Comparison was conducted between PMRT and non-PMRT subgroups.</p></sec><sec><title>Results</title><p>Of the 215 eligible patients, 35.8% (77/215) cT<sub>1-2</sub>N<sub>+</sub> patients achieved ypT<sub>0-2</sub>N<sub>0</sub> after NAC while 64.2% (138/215) of the patients remained nodal positive (ypT<sub>0-2</sub>N<sub>+</sub>). The 5-year DFS of ypT<sub>0-2</sub>N<sub>0</sub> non-PMRT was 79.5% (95% confidence interval [CI] 63.4-95.6%). No statistically significant difference was observed between the ypT<sub>0-2</sub>N<sub>0</sub> PMRT and non-PMRT subgroups for the 5-year DFS (78.5% vs 79.5%, <italic>p</italic> = 0.673) and OS (88.8% vs 90.8%, <italic>p</italic> = 0.721). The 5-years DFS didn’t obviously differ between the ypT<sub>0-2</sub>N<sub>0</sub> non-PMRT subgroup and cT<sub>1-2</sub>N<sub>0</sub> subgroup (79.5% vs 93.3%, <italic>p</italic> = 0.070). By using Cox regression model in multivariate analyses of prognosis in ypT<sub>0-2</sub>N<sub>+</sub> PMRT subgroup, HER2 overexpression and triple-negative breast cancer were significantly poor predictors of DFS and OS, while ypN stage was significant independent predictors of OS.</p></sec><sec><title>Conclusion</title><p>An effective response to NAC (ypT<sub>0-2</sub>N<sub>0</sub>) indicates a sufficiently favorable prognosis, and PMRT might be omitted for cT<sub>1-2</sub>N<sub>+</sub> breast cancer patients with ypT<sub>0-2</sub>N<sub>0</sub> after NAC.</p></sec>