Clinical importance of micrometastasis in sentinel lymph nodes

Introduction

We evaluated the incidence of micrometastasis and nonsentinel lymph node metastasis as well as local and axillary recurrence rates after level I-II axillary lymph node dissection.

Materials and methods

Patients (n = 760) with early-stage breast cancer underwent sentinel lymph node biopsy, and 45 patients (6.0%) with micrometastasis (0.2-2.0 mm) were included in this study. Data concerning tumor, patients’ characteristics and adjuvant treatments were recorded.

Results

The median age was 46 (26-67) years, median breast tumor size was 20 (1-50) mm, and median number of excised sentinel lymph nodes were 2 (1-5). All patients with micrometastasis underwent further level I-II axillary lymph node dissection. Eleven of 45 (24.4%) patients with micrometastasis in their sentinel lymph node biopsy had nonsentinel lymph node metastasis after an axillary lymph node dissection. There was no factor related to nonsentinel lymph node metastasis. Stage migration occurred in 4 of 45 patients (8.8%) due to the detection of micrometastases or macrometastases in nonsentinel lymph nodes.

Discussion

The classical treatment after detection of micrometastasis in sentinel lymph nodes is further axillary dissection. However, nonrandomized, nonprospective studies with 4-5 years follow up showed 0.6% axillary recurrence without further axillary lymph node dissection, although we still need the results of randomized controlled studies.