Predictive Factors for Non-Sentinel Lymph Node Metastasis in Patients With Clinically Node-Negative Ipsilateral Multiple Breast Cancer Treated With Total Mastectomy

We investigated the predictive factors for non-sentinel lymph node (SN) metastasis in ipsilateral multiple breast cancer and compared them with solitary breast cancer. The significant and potential factors in multiple breast cancer were pathologic invasion size and the number of positive SNs. These 2 could differentiate patients with positive non-SNs from those with negative non-SNs with high sensitivity. Background: Recent clinical trials have shown that axillary lymph node dissection can be omitted even with positive sentinel nodes (SN) unless the patient undergoes total mastectomy without irradiation. The aim of our study was to identify predictive factors for non-SN metastasis among patients with solitary or multiple breast cancer treated with total mastectomy. Patients and Methods: Clinically node-negative breast cancer patients with pathologically node-positive disease treated with total mastectomy and axillary dissection after SN biopsy were retrospectively analyzed. Significant pathologic predictive factors for positive non-SN metastasis were also examined. Results: There were 47 multiple and 143 solitary breast cancer patients. Pathologic diagnosis demonstrated that smaller invasion size but larger tumor size, including adjacent noninvasive cancer, was observed in multiple breast cancer. The number of involved SNs and the rate of non-SN metastasis were similar between the multiple and solitary groups. Regarding predictive factors for non-SN metastasis, lymphatic invasion and SN macrometastasis were significant factors in the solitary group, and pathologic invasion size > 2 cm was the only significant factor in the multiple group. Conclusion: Larger pathologic invasion size was important for predicting non-SN metastasis in multiple breast cancer.