Abstract
Background The impact of postmastectomy radiotherapy (PMRT) in patients receiving neoadjuvant chemotherapy (NAC) is unclear. The purpose of this study is to identify the patients who may benefit from PMRT. Methods We retrospectively analysed patients with clinical stage II-III breast cancer who underwent NAC and modified radical mastectomy at our centre from 2007 to 2015. We investigated the relationship amongst locoregional recurrence rate (LRR), disease-free survival (DFS), and clinical pathological characters. Results A total of 554 patients were analysed in this study. The median follow-up time was 65 months. Amongst the patients, 58 (10.5%) had locoregional recurrence, 138 (24.9%) had distant metastasis, and 72 (13.0%) patients died. The 5-year cumulative incidence of LRR and DFS was 9.2% and 74.2%, respectively. A total of 399 (72%) patients received PMRT and 155 (28%) did not. The 5-year LRR of the patients with PMRT (7.3% vs. 14.1%, P=0.01) decreased significantly. We found that PMRT was an independent prognostic factor of LRR and DFS. Patients with the persistent involvement of 1–3 lymph nodes (ypN1) and more than 4 positive lymph nodes (ypN2-3) had a better outcome after PMRT than those without. However, the LRR and DFS of patients with negative lymph nodes at the time of surgery (ypN0) and who received PMRT showed no significant benefits. Amongst all patients with the three molecular subtypes of breast cancer, patients with triple-negative breast cancer had the highest pathological complete response rate but the worst prognosis (P=0.001). Conclusion Results showed that PMRT significantly reduced the LRR of patients with clinical stage II-III breast cancer after receiving NAC and mastectomy. YpN0 patients derived no local control or survival benefit after receiving PMRT, whereas those with ypN1 and ypN2-3 could obviously benefit from PMRT.
Highlights
Neoadjuvant chemotherapy (NAC) is currently widely used in patients with locally advanced breast cancer to transform nonoperable cases into operable ones, improving breast preservation rates and reflecting the sensitivity of tumour cells to systemic therapy [1,2,3]
A total of 554 patients were analysed in this study. e median follow-up time was 65 months from diagnosis. e clinical and pathological characteristics of the patients are introduced in detail in Table 1. e median age at diagnosis was 51 years
No statistical difference in age, menstrual status, histological grade, pathological type, hormone receptor status, and HER-2 status was observed between the postmastectomy radiotherapy (PMRT) group and the non-PMRT group
Summary
Neoadjuvant chemotherapy (NAC) is currently widely used in patients with locally advanced breast cancer to transform nonoperable cases into operable ones, improving breast preservation rates and reflecting the sensitivity of tumour cells to systemic therapy [1,2,3]. A large number of studies have shown that postmastectomy radiotherapy (PMRT) can significantly reduce the locoregional recurrence rate (LRR) of patients with stage II-III breast cancer and increase overall survival (OS) [4, 5]. Bowel Project (NSABP) in the United States suggested that tumour response and pathological lymph node status are independent prognostic factors of LRR [14]. Is study mainly aimed to explore the independent prognostic factors affecting the LRR and disease-free survival (DFS) of patients with clinical stage II-III breast cancer undergoing NAC and mastectomy and to identify with increased accuracy the patients that should receive PMRT following NAC. E patients received adjuvant chemotherapy, radiotherapy, or endocrine therapy after NAC in accordance with the clinical pathological characteristics of the tumour. A two-sided P value of 0.05 was used as the alpha error for the consideration of statistical significance
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