Very slight chance of other metastases in axillary nodes of breast cancer patients with a small sentinel node metastasis without extranodal tumor growth

Objective. To determine in patients with mammary carcinoma and a sentinel node metastasis whether pathological parameters of the sentinel node metastasis and the primary tumour might have predictive value with respect to the presence of metastases in other axillary nodes. Design. Prospective. Method. The study group consisted of the first I00 consecutive patients with a sentinel node metastasis, who subsequently underwent a complete axillary dissection. The patients with metastases in the non-sentinel nodes were compared to those without such metastases regarding the size of the largest sentinel node metastasis and the presence of extranodal tissue invasion near any such node, and size, and type of the primary tumour. Results. The median size of the metastases in the sentinel lymph node in the two groups was 3 mm versus I3 mm respectively (p < 0.00I) and the frequency of extranodal tissue invasion 3% versus 74% respectively (p < 0.00I); the combination of these factors strongly predicted the presence of non-sentinel lymph node metastases in the axilla (94% area under the receiver operating characteristics curve). None of the 30 patients with a micrometastasis ≤ 2.0 mm in the sentinel lymph node had metastases in the non-sentinel axillary lymph nodes. Metastases were present in the non-sentinel axillary lymph nodes in 29 of the 3I patients with extranodal tissue invasion near the sentinel node. Conclusion. In breast cancer patients with a sentinel lymph node metastasis ≤ 2.0 mm and without extranodal tumour growth a complete axillary lymph node dissection might be unnecessary as the risk of additional metastases was very small.