Indications for sentinel lymph node biopsy in patients with breast cancer: retrospective and simulation analyses

The disease status of axillary lymph nodes at diagnosis is the most powerful predictor of prognosis for patients with breast cancer. Axillary lymph node dissection (ALND) has been the standard treatment. Recently, lymphatic mapping and sentinel lymph node biopsy (SNB) have been suggested as alternatives to ALND. However, a clear indication for SNB has not yet been established. The goal of this study was to determine which patients might best benefit from the SNB method.

A retrospective study compared the relationship of age, menopausal status, tumor size group, histology and clinical evaluation of nodes to histological axillary lymph node status in 5892 consecutive Japanese breast cancer patients who underwent ALND. A simulation analysis with reported SNB sensitivity and specificity was carried out.

Clinical lymph node evaluation was the most relevant factor to predict axillary nodal status. However, even patients with no clinical nodal involvement (N0) showed only 71% axillary nodal negativity. Tumor group based on tumor size and histology also related to axillary nodal status. The simulation analysis revealed that of patients with negative lymph node probability, more than 66% were good candidates for SNB.

The clinically negative node (N0) is the most important indication for SNB. Therefore, the candidates for SNB should be picked from the patients with N0. When no histological information is available, patients whose tumor is 20 mm or smaller are candidates for SNB. When histological information is available, the SNB indication extends to patients whose type of tumor has histologically good prognosis or a low probability of having nodal involvement, regardless of tumor size.