Cutaneous malignant melanoma: current views on pathogenesis, diagnosis, and surgical management.

Reliable cancer statistics reveal an unexplained increase in the incidence and rate of death from melanoma. Increased exposure to ultraviolet light does not seem to be a factor. Hormones may affect the incidence but do not influence survival. The recognition of the biologic evolution of different types of melanomas and the prognostic value of microstaging has had a major impact on the surgical management of cutaneous melanomas. Currently adequate excision is the only available curative treatment for melanoma and is most effective if performed on an early lesion. The extent of the excision should depend on the level of invasion and the bulk and location of the lesion. When clinically involved, dissection of the regional lymph nodes should be performed. The value of prophylactic node dissection of clinically uninvolved regional lymph nodes is unknown. Because of the low probability of regional lymph node involvement in thin lesions (less than 0.75 mm), prophylactic node dissection is not warranted. In contrast, there is a much higher incidence of spread to the regional lymph nodes reported in melanomas found to be thicker than 0.75 mm by microstaging. Prophylactic node dissection is probably worthwhile for these patients. Improved prospective randomized studies are needed to evaluate and determine the effectiveness of the various treatments that are being recommended.