Biostatistical Basis of Elective Node Dissection

Abstract

From 1954-1964, 259 individuals with primary malignant melanoma had elective node dissection. Microscopic metastases were found in 15% of these patients. The presence of only a microscopic focus of involvement gave a 10 yr cure rate of 67%; metastases larger than a microscopic focus in a single node, 50% and more than 1 node, 15%. One hundred and forty-five individuals were treated by wide excision alone with 18% subsequently requiring therapeutic lymphadenectomy with a 10 yr cure of only 6%. A prospective study was initiated which was concerned with the efficacy of selection of patients for elective node dissection. Clark''s level of invasion was determined for 258 patients treated since Jan., 1972. The depth of invasion of the primary lesion correlated directly with the absence of lymph node metastases, extent of nodal involvement and rate of recurrence. The concept of elective node dissection is valid.