Diagnosis, treatment and prognosis of early melanoma. The importance of depth of microinvasion.

There are many clinicopathologic features of the lesion and host which influence the natural course of melanoma. Currently, the most important prognostic factor appears to be the depth of invasion of the primary lesion. Using either the Clark's level of microinvasion or the tumor thickness as measured by Breslow, there is good correlation of decreasing survival rates, and increasing incidence of occult metastasis in regional nodes with deeper invasion of the tumor. Thus, proper diagnosis and treatment of primary melanoma depends on the information of depth of microinvasion. And patients with high-risk of developing occult metastasis in regional nodes can be identified. Although two recent studies question the value of performing prophylactic regional lymphadenectomy, none of these studies utilized depth of microinvasion to select patients who have a high chance of having extension or relapse only in regional nodes.