Prognostic significance of nodal involvement region in clinical stage IIIc breast cancer patients who received primary systemic treatment, surgery, and radiotherapy

•Involvement of both IMN and SCN was associated worse outcomes in cN3 breast cancer.•The majority of disease recurrence events were distant metastases.•HER2-overexpressing phenotype demonstrated favourable outcomes.•Individualised treatment strategies considering these finding should be provided.

ObjectivesTo evaluate the prognostic influence of involvement of both internal mammary nodes (IMNs) and supraclavicular nodes (SCNs) in clinical stage IIIc breast cancer patients who underwent primary systemic treatment, surgery, and radiotherapy (RT).Materials and methodsBetween 2001 and 2009, 110 breast cancer patients with IMN or SCN involvement were treated with primary systemic treatment followed by surgery and RT. The median age was 50 years. Clinical N-stage was cN3b and cN3c in 29 (26.4%) and 81 (73.6%) patients, respectively. Among the 81 patients with cN3c disease, 18 patients had both IMN and SCN involvement. Primary systemic treatment regimen was most commonly doxorubicin plus docetaxel (54.5%) or cyclophosphamide (20.0%). Mastectomy was performed in 71 (64.5%) patients. The RT dose delivered to the chest wall or whole breast was 50-50.4 Gy in 25-28 fractions. IMN and SCN regions were irradiated in 77 (70.0%) and 107 (97.6%) patients, respectively.ResultsAt a median follow-up of 57.4 months (range, 8.6-149.9 months), 44 patients (40.0%) developed disease recurrence. Among the 18 patients with both IMN and SCN involvement, 12 patients experienced disease recurrence and 11 of them had distant metastases. The 5-year disease-free survival (DFS) and overall survival (OS) of all patients were 60.2% and 75.5%, respectively. Decreased DFS and OS were observed in the 18 patients with both IMN and SCN involvement (5-year rates, 33.3% and 50.0%; P = 0.0051 and 0.0010, respectively).ConclusionInvolvement of both IMNs and SCNs was associated with worse survival outcomes in patients with clinical stage IIIc breast cancer.