Predictive Factors for Supraclavicular Lymph Node Recurrence in N1 Breast Cancer Patients

Background: The purpose of this study was to identify predictive factors for supraclavicular lymph noderecurrence (SCLR) in N1 breast cancer patients and define a high-risk subgroup who might benefit fromsupraclavicular nodal radiotherapy (RT). Materials and
Methods: From January 1995 to December 2009, 113breast cancer patients with 1 to 3 positive axillary lymph nodes were enrolled in this study. All patients underwentbreast-conserving surgery (BCS) or modified radical mastectomy (MRM). RT was given to all patients whoreceived BCS. Among the patients given MRM, those with breast tumors >5 cm in size received RT. Regionalnodal irradiation was not applied. Systemic chemotherapy was given to 105 patients (92.9%). Patient data wereretrospectively reviewed and analyzed to identify predictive factors for SCLR.
Results: The median follow-upduration was 6.5 years, with 5- and 10-year actuarial SCLR rates of 9.3% and 11.2%, respectively. Factorsassociated with SCLR on univariate analysis included histologic grade, number of dissected axillary lymph nodes,lymphovascular invasion, extracapsular extension (ECE), and adjuvant chemotherapy. On multivariate analysis,histologic grade and ECE remained significant. The patient group with grade 3 and ECE had a significantlyhigher rate of SCLR compared with the remainder (5-year SCLR rate; 71.4% vs. 4.0%, p<0.001).
Conclusions:Histologic grade and ECE status are significant predictive factors for SCLR. Supraclavicular nodal RT isnecessary in N1 breast cancer patients featuring histologic grade 3 and ECE.