Impact of Postmastectomy Radiation Therapy on Breast Cancer Patients According to Pathologic Nodal Status after Modern Neoadjuvant Chemotherapy

Abstract

The utility of postmastectomy radiation therapy (PMRT) for breast cancer patients after neoadjuvant chemotherapy (NAC) is highly controversial. This study evaluated the impact of PMRT according to pathologic nodal status after modern NAC. Materials and MethodsWe retrospectively reviewed 682 patients with clinical stage II-III breast cancer who underwent NAC and mastectomy from 2013 to 2017. In total, 596 (87.4%) patients received PMRT, and 86 (12.6%) did not. We investigated the relationships among locoregional recurrence-free survival (LRRFS), disease-free survival (DFS), overall survival (OS), and various prognostic factors.Subgroup analyses were also performed to identify patients who may benefit from PMRT. ResultsThe median follow-up duration was 67 months. In ypN+ patients (n=368, 51.2%), PMRT showed significant benefits in terms of LRRFS, DFS, and OS (all p < 0.001). In multivariate analyses, histologic grade (HG) III (p=0.002), lymphovascular invasion (LVI) (p=0.045), and ypN2-3 (p=0.02) were significant risk factors for poor LRRFS. In ypN1 patients with more than two prognostic factors among luminal/HER2-negative subtype, HG I-II, and absence of LVI, PMRT had no significant effect on LRRFS (p=0.18). In ypN0 patients (n=351, 48.8%), PMRT was not significantly associated with LRRFS, DFS, or OS. However, PMRT showed better LRRFS in triple-negative breast cancer (TNBC) patients (p=0.03). ConclusionPMRT had a major impact on treatment outcomes in patients with residual lymph nodes following NAC and mastectomy. Among ypN0 patients, PMRT may be beneficial only for those with TNBC.

The Role of Sentinel Lymph Node Biopsy in Breast Cancer Patients Who Become Clinically Node-Negative Following Neo-Adjuvant Chemotherapy: A Literature Review

“…Cho et al [75] described no differences in 5-year DFS and OS even in this setting of patients who were subsequently treated or not by RT. Kim et al [76] evidenced no statistically significant differences in 5-year LRRFS and described that RT improves LRRFS only in TNBC patients; for these reasons, the optimal combination of surgery and RT in this context is still up for debate [68]. There is a great expectation for prospective data to be presented by ongoing studies, for example the NSABPB-51/RTOG1304 trial [77] and the Alliance clinical trial [78], from the perspective of a possible de-escalation of radiotherapy for such patients.…”

Analysis of Individualized Silicone Rubber Bolus Using Fan Beam Computed Tomography in Postmastectomy Radiotherapy: A Dosimetric Evaluation and Skin Acute Radiation Dermatitis Survey

“…Postmastectomy radiotherapy (PMRT) has been found to significantly reduce the local recurrence rate (LRR) and prolong the overall survival (OR). 1 , 2 Bolus, a tissue-equivalent material, has been widely used to improve the chest wall dose during radiation treatment. By overcoming the influence of the dose-building effect, bolus can achieve suitable target dose distribution, which is essential for cancer treatment.…”