Regional lymph node metastases and the level of invasion of primary melanoma.

One hundred and nineteen patients with primary malignant melanoma had their primary lesion classified according to Clark's level of invasion by Clark and the Division of Surgical Pathology at UCLA. Thirty patients had superficial melanoma (Level II) and did not undergo regional lymph node dissection (RLND). All other patients (Levels III, IV, and V) underwent regional lymph node dissection. Thirty-two percent of patients with Level III melanoma, 67% of patients with Level IV melanoma, and 66% of patients with Level V melanoma had metastases to the regional lymph nodes. These studies suggest that the level of invasion, or the thickness of the primary melanoma, is helpful for predicting regional lymph node metastases.