Determining which patients require irradiation of the supraclavicular nodal area after surgery for N1 breast cancer

Purpose: We designed this study to determine which patients have a high risk of supraclavicular node recurrence in N1 breast cancer previously treated with surgery but not having received supraclavicular radiation therapy (SCRT) and to identify which patients needed SCRT. Methods and Materials: We performed a retrospective review of 448 pathologic N1 breast cancer patients treated with mastectomy or breast-conserving treatment, but without SCRT, between 1994 and 2003. Mastectomy was performed in 302 patients (67.4%). The median number of axillary nodes dissected was 17 (range, 5-53). Systemic chemotherapy was administered in 443 patients (98.9%), and 144 patients received radiation after breast-conserving surgery. The median follow-up was 88 months (range, 15-170 months). Results: At follow-up, the treatment failed in 101 patients (22.5%), and 39 patients (8.7%) had supraclavicular node recurrence. Prognostic factors in supraclavicular node recurrence included lymphovascular invasion (p < 0.0001), extracapsular extension (p < 0.0001), the number of involved axillary nodes (p = 0.0003), and the level of involved axillary nodes (p = 0.012) in univariate and multivariate analyses. The total number of prognostic factors correlated well with supraclavicular node recurrence. In the analysis of 5-year supraclavicular node recurrence-free survival, patients with two or more factors showed a significantly higher recurrence rate than did patients with fewer than two factors (96.8% and 72.9%, respectively; p < 0.0001). Conclusions: The prognostic factors associated with supraclavicular node recurrence were lymphovascular invasion, extracapsular extension, and the number and level of involved axillary nodes. Patients with two or more prognostic factors might benefit from SCRT.