Prognostic factors related to survival and groin recurrence following therapeutic lymph node dissection for lower limb malignant melanoma.

A retrospective analysis was carried out of 133 patients undergoing therapeutic lymph node dissection for malignant melanoma of the lower limb. A radical ilio-obturator dissection (RID) was performed in 106 patients and a superficial femoral dissection (SFD) in the remaining 27. On univariate analysis five factors were found to be significant indicators of prognosis. These were: Clark level of the primary (P = 0.02); primary melanoma thickness (P = 0.04); total number of positive nodes (P less than 0.001); number of positive femoral nodes (P less than 0.001); and number of positive ilio-obturator nodes (P less than 0.001). On multiple regression analysis only the number of positive nodes in each compartment remained a significant independent factor (P less than 0.001). The morbidity associated with RID was not significantly greater than after SFD. RID was, however, associated with a reduction in subsequent groin recurrence. Radical nodal clearance is the operation of choice. This technique provides maximum prognostic information, reduces the likelihood of local untreatable disease and possibly improves overall survival rates--especially when only one iliac node is involved.