Macrometastasis, micrometastasis, and isolated tumor cells in sentinel lymph nodes of early breast cancers: A 10-year histopathological and survival analysis of 537 Asian patients

Abstract

© 2015 Société Internationale de Chirurgie. Background: In patients with negative sentinel lymph node biopsy (SLNB), axillary dissection (AD) can be avoided to reduce morbidities. However, there is only limited data on the rate of positive non-SLN (NSLN) in those who have micrometastasis and isolated tumor cells (ITC) in the literature. Methods: We did a retrospective review of all clinically node-negative breast cancer patients with SLNB done at our unit from January 2001 to June 2011. Multivariate analysis was adopted to evaluate the risk factors for NSLN metastasis. Difference in 5-year disease-free survival (DFS) was evaluated with log-rank test. Results: Five-hundred and thirty-seven patients underwent SLNB; 161 (30 %) had positive SLN on frozen section (FS), 50 of these patients (31 %) had NSLN metastasis, 25 patients had negative SLN on FS but were found to have micrometastasis on histopathology, and only 1 (4 %) of them had NSLN metastasis, while 14 patients were found to have ITC in SLN; none of them had NSLN metastasis. Multivariate analysis found that the number of SLN harboring micrometastasis is the only independent risk factor for NSLN metastasis in patients with micrometastasis (p value = 0.008). On the contrary; tumor size, grade, and biology were not associated with NSLN metastasis. 5-year DFS in patients with macrometastasis in SLN was 94.2 %, while that in patients with micrometastasis and ITC was 100 % (p value <0.001). Conclusion: NSLN metastasis in those who only have micrometastasis and ITC is rare, and 5-year DFS is significantly better in this group of patients as well. It is therefore a routine practice in our unit to omit AD in patients with micrometastasis and ITC on SLN.