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

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

doi:10.3389/fonc.2022.881047

Postmastectomy Radiotherapy After Neoadjuvant Chemotherapy in cT_1-2N₊ Breast Cancer Patients: A Single Center Experience and Review of Current Literature

Front Oncol. 2022 May 17:12:881047. doi: 10.3389/fonc.2022.881047. eCollection 2022.

Authors

Meng Luo^{1

2}, Huihui Chen^{1

2}, Hao Deng¹, Yao Jin¹, Gui Wang³, Kun Zhang¹, Hong Ma¹, Yiding Chen^{1

2

4}, Suzhan Zhang^{1

2

4}, Jiaojiao Zhou^{1

2

4}

Affiliations

¹ Department of Breast Surgery and Oncology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
² The Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang University School of Medicine, Hangzhou, China.
³ Department of General Surgery, Longquan People's Hospital, Longquan, China.
⁴ Cancer Center, Zhejiang University, Hangzhou, China.

Abstract

Purpose: Postmastectomy radiotherapy (PMRT) after neoadjuvant chemotherapy (NAC) in breast cancer patients with initial clinical stage cT_1-2N₊, especially for those who achieved ypT_1-2N₀, is still controversial. This study was to evaluate the survival prognosis of cT_1-2N₊ patients after NAC with or without PMRT, and to discuss the selection of patients who may omit PMRT.

Patients and methods: From January 2005 to December 2017, 3055 female breast cancer patients underwent mastectomy in our medical center, among whom 215 patients of cT_1-2N₊ 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.

Results: Of the 215 eligible patients, 35.8% (77/215) cT_1-2N₊ patients achieved ypT_0-2N₀ after NAC while 64.2% (138/215) of the patients remained nodal positive (ypT_0-2N₊). The 5-year DFS of ypT_0-2N₀ non-PMRT was 79.5% (95% confidence interval [CI] 63.4-95.6%). No statistically significant difference was observed between the ypT_0-2N₀ PMRT and non-PMRT subgroups for the 5-year DFS (78.5% vs 79.5%, p = 0.673) and OS (88.8% vs 90.8%, p = 0.721). The 5-years DFS didn't obviously differ between the ypT_0-2N₀ non-PMRT subgroup and cT_1-2N₀ subgroup (79.5% vs 93.3%, p = 0.070). By using Cox regression model in multivariate analyses of prognosis in ypT_0-2N₊ 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.

Conclusion: An effective response to NAC (ypT_0-2N₀) indicates a sufficiently favorable prognosis, and PMRT might be omitted for cT_1-2N₊ breast cancer patients with ypT_0-2N₀ after NAC.

Keywords: breast cancer; disease-free survival; neoadjuvant chemotherapy; overall survival; postmastectomy radiotherapy.