Regional lymph node dissection for malignant melanoma of the extremities.

Seven hundred thirty-nine patients with malignant melanoma of the extremities were treated with a uniform surgical approach that included wide and deep excision of the primary site and regional node dissection therapeutically and electively for invasive lesions (Clark's levels III, IV, and V). Of the 490 patients who underwent lymph node dissections, follow-up was available for 457 (93%). Life-table comparison of 362 patients with histologically negative nodes to 95 with histologically proved lymph node metastases yielded statistically significant differences in survival (P less than 0.001). Five-year cumulative survival rates were 91% in the group without and 48% in the group with nodal metastases. Among histologically positive patients, differences in life-table survival curves for the 60 clinically negative patients compared to the 35 clinically positive patients were also statistically significant (P = 0.004); 5-year cumulative survival rates were 57% for the former group and 33% for the latter. Although there appears to be an advantage to regional lymph node dissection for micrometastases as opposed to gross nodal involvement, for the majority of patients metastatic melanoma in these nodes is the major indicator of systemic disease.