Analysis of the Clinicopathological Features in the Micrometastasis and the Macrometastasis in Sentinel Lymph Node of Primary Breast Cancer

ABSTRACT

PURPOSE: The aim of this study was to compare the micrometastasis group with the macrometastasis group, and to analyze clinical and pathological variables to determine what factors might predict non-sentinel lymph node (NSLN) involvement in the women with sentinel nodes that contained only micrometastasis. METHODS: Between June 2003 and September 2005, 650 patients with primary breast cancer and who underwent a SLN procedure were retrospectively reviewed. Of those 650 patients, 138 patients with metastasis in the SLNs were analyzed. RESULTS: The median number of harvested sentinel lymph nodes (SLNs) was 2.5 (range 1~7) and the median number of tumor positive LNs was 2.1 (range 1~22). Of the 138 patients with a positive SLN, macrometastasis was identified in 105 patients and micrometastasis was noted in 33 patients. The SLN micrometastases were smaller than 0.2 mm in 18 patients and it was between 0.2 to 2.0 mm in 15 patients. Completion axillary dissection was performed in 17 (51.5%) patients with SLN micrometastasis and in 105 (100%) patients with SLN macrometastasis. NSLN involvement was found in 43/105 (41.0%) patients with SLN macrometastasis, while it was not found in the patients with SLN micrometastasis. Univariate analysis showed that T stage, multiplicity, lymphovascular invasion and histologic type were significantly associated with the difference between micrometastasis and macrometastasis in the SLNs. Multivariate analysis identified T stage as a significant factor. CONCLUSION: This study suggests that NSLN metastasis is associated with size of metastasis found in the SLN and completion axillary dissection may not be necessary in patients who have micrometastatic disease in the SLN.