Radiation Treatment in Pathologic N0-N1 Patients Treated with Neoadjuvant Chemotherapy Followed by Surgery for Locally Advanced Breast Cancer

PURPOSE: This study evaluated the treatment results and the necessity to irradiate the supraclavicular lymph node (SCN) region in pathological N0-N1 (pN0-N1) patients with locally advanced breast cancer treated with neoadjuvant chemotherapy (NAC) followed by surgery and radiotherapy (RT). METHODS: Between 1996 and 2008, 184 patients with initial tumor size >5 cm or clinically positive lymph nodes were treated with NAC followed by surgery and RT. Among these patients, we retrospectively reviewed 98 patients with pN0-N1. Mastectomy was performed in 55%. The pathological lymph node stage was N0 in 49% and N1 in 51%. All patients received adjuvant RT to chest wall or breast and 56 patients (57%) also received RT to the SCN region (SCNRT). RESULTS: At 5 years, locoregional recurrence (LRR)-free survival, distant metastasis-free survival, disease-free survival (DFS), and overall survival rates were 93%, 83%, 81%, and 91%, respectively. In pN0 patients, LRR was 7% in SCNRT- group and 5% in SCNRT+ group. In pN1 patients, LRR was 7% in SCNRT- group and 6% in SCNRT+ group. There was no significant difference of LRR, regardless of SCNRT. However, in pN1 patients, there were more patients with poor prognostic factors in the SCNRT+ group compared to SCNRT- group. These factors might be associated with worse DFS in the SCNRT+ group, even though RT was administered to the SCN region. CONCLUSION: Our study showed the similar LRR, regardless of SCNRT in pN0-pN1 breast cancer patients after NAC followed by surgery. Prospective randomized trial is called for to validate the role of SCNRT.