Evaluation of sentinel lymph node biopsy prior to axillary lymph node dissection: the role of isolated tumor cells/micrometastases and multifocality/multicentricity-a retrospective study of 1214 breast cancer patients.

PURPOSE: Sentinel lymph node biopsy (SLNB) alone has thus become an accepted surgical approach for patients with limited axillary metastatic disease. We investigated to what extent isolated tumor cells (ITC) or micrometastasis in SLNBs is associated with proven tumor cells or metastasis in non-sentinel lymph nodes. Furthermore, we investigated the feasibility of SLNB in multifocal and multicentric tumors as both entities have been considered a contraindication for this technique.

METHODS: 1214 women suffering from T1 and T2 invasive breast cancer, with clinically and sonographically insuspect axillary status and undergoing primary breast cancer surgery including SLNB and axillary staging in case of SLN (sentinel lymph node) metastases, were recruited into this multicentered study.

RESULTS: ITC and micrometastases were found in 2.01 and 21.4% of patients with SLN metastases (n = 299). Among patients with sentinel micrometastases, 4.7% showed further axillary micrometastases, while only two patients (3.1%) had two axillary macrometastases. Multifocal and multicentric tumors were diagnosed in 9.3 and 2.6% of our patients who at least had one SLN resected, respectively. Detection rates of SLNs did not differ between the cohorts suffering from unicentric and multifocal or multicentric disease. Moreover, the portion of tumor-free SLNs, the number of SLNs with metastasis as well as the mean number of resected SLNs did not differ.

CONCLUSIONS: No patient with sentinel node micrometastases showed more than two axillary macrometastases. Multifocal and multicentric disease is no contraindication for SLNB.