Efficacy of elective lymph node dissection in patients with intermediate thickness primary melanoma.

One of the most controversial areas in the management of malignant melanoma concerns the efficacy of prophylactic lymph node dissection. During a retrospective computer-aided data review of over 3000 melanoma patients referred to the Duke University Cancer Center, 613 patients with complete staging along with surgical and pathologic data, having trunk and extremity melanoma, were identified with Breslow thickness in the range of 0.76 to 4.0 mm. One hundred eighty-seven of these clinically node-negative patients received an elective lymph node dissection (WLE/ND). The remaining patients were treated only with an initial wide local excision (WLE) at the time of diagnosis of their melanomas. There was no difference in age at diagnosis or male-female ratio between the treatment groups. A higher percentage of the WLE/ND group (36% vs. 31%) showed ulceration of their primary lesions and a greater mean tumor thickness (1.81 +/- 0.80 mm vs. 1.60 +/- 0.73 mm) than the WLE patients. Despite the force of these two adverse prognostic factors in the WLE/ND group, only ten deaths (5%) have occurred in the elective lymph node group compared to 51 (12%) in the control group. Using a multifactorial analysis to control for the prognostic contribution of the two most informative variables in stage I melanoma, Breslow thickness and ulceration, WLE/ND had an independent favorable effect on survival (p = 0.01). There was no apparent additional benefit to lymph node dissection in patients whose primary lesion measured less than 0.76 mm or greater than 4.0 mm in thickness. The surgeon may use survival estimates with and without elective node dissection based on a prognostic equation ("prognostigram") as a quantitative aid to treatment planning.