P3-07-07: Effect of Sentinel Lymph Node Biopsy without Axillary Lymph Node Dissection on Overall Survival in Patients with T1 or T2 Node-Positive Breast Cancer: A Report from the Korean Breast Cancer Society.

Abstract Introduction: Sentinel lymph node biopsy (SLNB) is accepted as an alternative method to axillary lymph node dissection for staging axillary lymph node status in clinically node-negative breast cancer. Current practical guidelines recommend that axillary lymph node dissection (ALND) should be performed in cases with sentinel node metastasis, and most of node-positive patients should receive adjuvant systemic therapy to reduce locoregional/distant recurrence and to improve overall survival irrespective of the number of lymph node metastasis. However, patients with ALND are more likely to develop lymphedema than those with SLNB alone, and appropriate systemic chemotherapy or hormone therapy significantly reduce locoregional and distant recurrence in early breast cancer patients. For this reason, the previous prospective study, American College of Surgeon Oncology Group Z0011 trial, was conducted and it suggested that there is no difference in overall survival between node-positive patients who received breast conserving treatment with SLNB alone and those with ALND after SLNB. This study is aimed to evaluate the difference of survival between node-positive patients who underwent SLNB alone and those who received ALND after SLNB using the Korean Breast Cancer Society registry. Methods: In 87671 patients with breast cancer in the registry, we enrolled 2581 patients who meet the eligible criteria in the study. All enrolled patients had T1 or T2 breast cancer, and received mastectomy or breast conserving treatment followed by documented adjuvant systemic therapy between Jan. 2001 and Apr. 2011. Log-rank test and Cox-proportional hazard model were used to access the difference of overall survival according to the axillary procedure. Results: There were 197 patients with SLNB alone and 2384 patients with ALND after SLNB, respectively. Smaller tumor size, lower number of nodal metastasis, and higher proportion of breast conserving surgery were shown in patients with SLNB alone than in those with ALND after SLNB. There was no significant difference in overall survival between 2 groups in the log-rank test. ALND after SLNB showed no significant improvement on overall survival in Cox-propotional hazard model adjusted by tumor size, number of nodal metastasis, and operation type (P=0.78, HR=0.73, 95% CI=0.08−6.62). Conclusion: The current study suggests that ALND after SLNB in cases with sentinel lymph node metastasis may not influence on the improvement of overall survival and supports the results of Z0011 trial. Further validation studies are necessary to expand the understanding of the role of performing SLNB alone in patients with node-positive breast cancer. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-07-07.