Malignant melanoma: Mayo Clinic experience.

To present the Mayo Clinic experience with treatment of melanoma of the trunk and extremities, we reviewed previous Mayo Clinic studies on the management of malignant melanoma and summarized the survival data and treatment-related outcome. A prospective trial involving elective lymph node dissection in 171 patients with malignant melanoma showed no advantage in overall survival and disease-free survival in the group whose nodes were removed. In an assessment of the treatment variables, a Cox stepwise multiple regression analysis showed a strong correlation of lesion thickness and level of invasion with survival. Another study of 535 patients with melanomas that involved the trunk and extremities, who were treated at the Mayo Clinic between 1971 and 1980, showed an overall survival of 83%. Patients with thin lesions (less than 0.76 mm thick) had a 98% 5-year survival, whereas patients with lesions 4 mm thick or thicker had only a 45% 5-year survival. Because the Mayo Clinic prospective randomized study showed no benefit for patients with melanoma who undergo immediate or delayed lymphadenectomy in the trunk and extremities, we do not perform elective lymph node dissection; however, close follow-up of patients is instituted, and lymph node dissection is performed when nodal involvement is first suspected.