Is There a Role for Post-Mastectomy Radiotherapy for T1-2N1 Breast Cancers With Node-Positive Pathology After Patients Become Node-Negative Pathology Following Neoadjuvant Chemotherapy?

Abstract

Purpose: To assess the benefit of post-mastectomy radiotherapy (PMRT) in breast cancer (BC) patients with T1-2N1M0 who developed pathologically negative lymph nodes (ypN0) after undergoing neoadjuvant chemotherapy (NAC) and mastectomy. Patients and Materials: Patients with T1-2 tumors and positive lymph node(s) who became pN0 after NAC and mastectomy were screened from our prospectively maintained database. The primary endpoint was recurrence-free survival (RFS), and the secondary endpoints were local recurrence-free survival (LRFS) and overall survival (OS). Propensity-score matching (PSM) was conducted for the comparison between PMRT and non-PMRT groups. Results: Of the 142 eligible patients, 110 (77.5%) received PMRT, and 32 (22.5%) did not. The median follow-up time was 72 months. Univariate analyses showed that the 5-year RFS, LRFS, and OS rates were 88.7, 94.5, and 96.1, respectively, with PMRT and 72.4, 90.1, and 95.0% without PMRT ( p = 0.028; p = 0.151; p = 0.971). Multivariate analyses established PMRT as a significant prognostic factor for RFS rate (HR, 0.411; 95% CI, 0.175–0.968; p = 0.042). After a PSM analysis (64 in the PMRT group vs. 32 in the non-PMRT group), PMRT remained significant, with improved RFS in univariate and multivariate analysis (with 5-year RFS rates of 90.1 vs. 72.4%, respectively, p = 0.016; HR, 0.323, 95%CI, 0.115–0.913, p = 0.033). In the subgroup of 48 (33.8%) patients with pathologic complete responses (pCR, ypT0, and ypN0) after NAC, PMRT did not affect RFS (HR, 0.226; 95% CI, 0.034–1.500; p = 0.123). Conclusions: PMRT might benefit pT1-2N1M0 patients with pN0 after NAC. Patients with pCR might consider omitting PMRT. Prospective studies are needed to assess the effect of PMRT on this specific patient population.

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.…”

“…The summary of the literature search and a comparison of the nine studies to our results are presented in Table 6. Five out of nine studies presented with OS analysis, within which three study [13,14,18] found that PMRT didn't improve OS in cN + who achieving ypN 0 after NAC, while another two [12,15] found that PMRT signi cantly improved OS in cN + patients after NAC, whatever achieving ypN 0 or still remaining ypN + patients. Besides the primary endpoint of OS, other endpoints (e.g.…”

Adjuvant locoregional radiation therapy in breast cancer patients with pathologic complete response after neoadjuvant chemotherapy: A systematic review and meta-analysis

“…The initial search on PubMed yielded 1837 studies. After applying the inclusion and exclusion criteria, 13 studies were included in the meta-analysis [13] , [14] , [15] , [16] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] . Fig.…”

“…A subgroup analysis was performed including three studies with data on the impact of LRRT on LRR in patients with pCR (both ypT0 and ypN0) [13] , [14] , [15] . In total, 390 patients were included in the analysis, 242 received LRRT and 148 did not.…”

“…However, the prognostic significance of pCR after NACT and the lack of convincing evidence on the impact of LRRT on patients with pCR after NACT has made the usage of LRRT in this setting questionable [8] , [9] , [10] , [11] , [12] . In fact, some studies have shown that LRRT in patients with pCR after NACT reduces the risk of LRR, whereas another study have failed to confirm these results [13] , [14] , [15] . Due to the limited evidence and conflicting results from existing research, there is a lack of consensus regarding the use of LRRT in clinical T3 and/or lymph node metastatic breast cancer patients with favorable response after NACT [16] .…”