Sentinel lymph node micrometastasis may predict non-sentinel involvement in cutaneous melanoma patients.

Objective: Cutaneous melanoma patients with positive sentinel lymph node biopsy (SLNB) are being treated with completion lymph node dissection (CLND). The aim of our study was to determine the predictive value of sentinel lymph node (SLN) micrometastases (metastases less than 2 mm in diameter) in assessing further lymph node involvement in CLND.

Methods: Between 2001 and 2005, we performed 476 SLNB in patients with stages I and II melanoma; 74 had metastases in SLN. We evaluated retrospectively the metastases in SLN according to their size and number. The presence of additional metastases in non-sentinel lymph nodes after CLND was evaluated.

Results: Thirty-nine patients had micrometastases, 22 of them were solitary, 3 were double, and 14 patients had multiple micrometastases in SLN. Out of 22 solitary micrometastases, no patient had additional metastases in non-sentinel lymph nodes. From 3 patients with double micrometastases, 1 patient had further metastases in non-sentinel lymph nodes after CLND. Out of 14 patients with multiple micrometastases, 2 had additional metastases in CLND.

Conclusions: No patient with a single SLN micrometastasis had further metastases after CLND in our series. CLND may not be beneficial after detecting a single micrometastasis in SLN.