Impact of Postmastectomy Radiotherapy on Locoregional Control and Disease-Free Survival in Patients with Breast Cancer Treated with Neoadjuvant Chemotherapy

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.

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

“…To further assess whether PMRT can benefit patients after NAC, the PubMed database was systematically searched for using the search terms, “postmastectomy radiation therapy”, “neoadjuvant chemotherapy” and “breast cancer”, for studies of PMRT after NAC published from March 1993 to November 2021. Of the 184 articles identified, nine ( 13 – 21 ) report results similar to ours ( Table 6 ). Eight of these studies reported the results of event-free survival analysis, such as locoregional recurrence (LRR), local recurrence free survival (LRFS), DFS, recurrence-free survival (RFS), and distant metastasis-free survival (DMFS) ( 13 – 16 , 18 – 21 ), whereas six studies reported OS and cause-specific survival (CSS) rates ( 13 – 17 , 20 ).…”

“…Of the 184 articles identified, nine ( 13 – 21 ) report results similar to ours ( Table 6 ). Eight of these studies reported the results of event-free survival analysis, such as locoregional recurrence (LRR), local recurrence free survival (LRFS), DFS, recurrence-free survival (RFS), and distant metastasis-free survival (DMFS) ( 13 – 16 , 18 – 21 ), whereas six studies reported OS and cause-specific survival (CSS) rates ( 13 – 17 , 20 ).…”

“…That study, however, found that PMRT significantly improved RFS but not LRFS, whereas rates of locoregional recurrence and distant metastases did not difference in patients who did and did not receive PMRT. A recent study of 554 clinical stage II-III patients found that PMRT after NAC significantly reduced 5-year LRR in clinical stage II-III patients, but had no local control or survival benefit in patients with ypN 0 after NAC ( 21 ).…”

Postmastectomy radiotherapy after neoadjuvant chemotherapy in cT1-2N+ breast cancer patients: a single center experience and review of current literature

“…The PubMed literature search resulted in 184 articles related to PMRT after NAC (from 1993 Mar to 2021 Nov), by using search terms "postmastectomy radiation therapy" "neoadjuvant chemotherapy" and "breast cancer" in all their forms. After reviewing the abstracts and full texts of all these literatures, nine studies [11][12][13][14][15][16][17][18][19] were found to report results comparable to our study. The summary of the literature search and a comparison of the nine studies to our results are presented in Table 6.…”

“…It is needed to point out that, in their study, the locoregional recurrence or distant metastasis rate was with no difference between PMRT and non-PMRT group. The latest study by Zhang (2021) [19] of 554 clinical stage II-III patients, demonstrated that PMRT signi cantly reduced 5-years LRR in clinical stage II-III patients after NAC, however those with ypN 0 derived no local control or survival bene t from PMRT.…”