Patients with N1 breast cancer: who could benefit from supraclavicular fossa radiotherapy?

Abstract

Purpose: To find a high-risk group of supraclavicular fossa recurrence (SCFR) in N1 breast cancer treated with breast conservative therapy without supraclavicular radiation therapy (SCFRT).

Methods and materials: We designed a retrospective review of 767 patients with N1 breast cancer. All patients included in this study underwent to lumpectomy or quadrantectomy with axillary lymph node dissection, followed by whole breast irradiation. All patients received radiotherapy with two tangencial fields, after a median dose of 50.4 Gy on the whole breast; an additional boost (10-16 Gy) to the tumor bed was administered. A analysis by the cox method was performed to identify prognostic factors for SCFR and a risk group for SCFR was build.

Results: With a median follow-up of 76 months (12-142 months), 81 patients (10.5%) had SCFR. With the exception of T stage, all other prognostic factors (lymphovascular invasion, extracapsular extension, the number of involved axillary nodes, estrogen receptor, T stage and nuclear grade) maintaned a statistical significance in the multivariate analysis. The risk group build consisted of patients with 1 or none prognostic factor, 2 and 3 or more prognostic factors. In the analysis of 5-years SCFR free survival, patients with ≥ 3 factors showed a significant higher recurrence rate than patients with 2 and 1 or none factors 44.1%, 91.1% and 97.7%, (p < 0.0001) respectively.

Conclusions: Extracapsular extension, lymphovascular invasion, high nuclear grade, negative hormone receptor and the number of involved axillary nodes were important prognostic factors associated with SCFR.

Keywords: Adjuvant radiotherapy; Breast cancer; Overall survival; Prognostic factors; Supraclavicular fossa recurrence.