Is elective nodal irradiation beneficial in patients with pathologically negative lymph nodes after neoadjuvant chemotherapy and breast-conserving surgery for clinical stage II–III breast cancer? A multicentre retrospective study (KROG 12-05)

Abstract

Background:To evaluate the effects of elective nodal irradiation (ENI) in clinical stage II–III breast cancer patients with pathologically negative lymph nodes (LNs) (ypN0) after neoadjuvant chemotherapy (NAC) followed by breast-conserving surgery (BCS) and radiotherapy (RT).Methods:We retrospectively analysed 260 patients with ypN0 who received NAC followed by BCS and RT. Elective nodal irradiation was delivered to 136 (52.3%) patients. The effects of ENI on survival outcomes were evaluated.Results:After a median follow-up period of 66.2 months (range, 15.6–127.4 months), 26 patients (10.0%) developed disease recurrence. The 5-year locoregional recurrence-free survival and disease-free survival (DFS) for all patients were 95.5% and 90.5%, respectively. Pathologic T classification (0−is vs 1 vs 2–4) and the number of LNs sampled (<13 vs ⩾13) were associated with DFS (P=0.0086 and 0.0012, respectively). There was no significant difference in survival outcomes according to ENI. Elective nodal irradiation also did not affect survival outcomes in any of the subgroups according to pathologic T classification or the number of LNs sampled.Conclusions:ENI may be omitted in patients with ypN0 breast cancer after NAC and BCS. But until the results of the randomised trials are available, patients should be put on these trials.

De-escalation of axillary irradiation for early breast cancer – Has the time come?

“…In BCT patients, among 5032 cT1-3 N1 undergoing PST (NCDB 2003-2011), no benefit from the addition of RNI to WBI was seen, both in ypN0 and ypN+ patients [59]. Also, in the ACOSOG Z1071, the BCT subgroup of the KROG 12-05 and among 9474 patients from another NCDB series (2010-2015), no benefit from RNI was observed, irrespective of pathological nodal status [42,61,70]. In a series of 248 ypN0 patients from Centre René Huguenin (Saint-Cloud, France) no difference in DFS and OS in relation to the RNI use was seen both among cN0 (164 patients) and cN+ (84 patients) subgroups [68].…”

Radiation Therapy Decision and Field Design after Neoadjuvant Chemotherapy in Breast Cancer: A Review of Neoadjuvant Approach

“…However, DFS was significantly worse for ypN1 patients without RNI. In the Korean experience of RNI in 260 stage II/III patients who were ypN0 after NAC [111] all patients had BCS. Regional nodes were treated in 52% of the cohort, 5% including IMN.…”

Clinical outcomes according to molecular subtypes in stage II-III breast cancer patients treated with neoadjuvant chemotherapy followed by surgery and radiotherapy

“…Updated results showed a sustained improvement in survival outcomes, and provided new insight into the relationship between pathological complete response and clinical outcomes in HER2‐enriched tumors . Against this backdrop, the Korean Radiation Oncology Group (KROG) recently conducted a multicenter retrospective study of the optimal radiotherapy field or irradiation omission in patients with ypN0 after NAC followed by breast‐conserving surgery (BCS) or mastectomy . In this study, information regarding the hormone receptor status and HER2 receptor status, which are known to be associated with tumor response and treatment results, was limited.…”