Addition of an Iliac/Obturator Lymph Node Dissection Does Not Improve Nodal Recurrence or Survival in Melanoma

Abstract

Controversy exists regarding the value and indications for inguinal dissection alone or in combination with an iliac/obturator lymph node dissection for melanoma. We reviewed patients from a multicenter prospective clinical trial and a single center who underwent inguinal dissection alone or combined with an iliac/obturator dissection for cutaneous melanoma. Analyses were stratified and compared by microscopic or macroscopic (palpable or detected by imaging) disease. The study was composed of 134 patients with a median follow-up of 39 months. Indications for inguinal dissection were microscopic disease in 94 (70%) patients and macroscopic nodal disease in 40 (30%) patients. An iliac/obturator dissection yielded tumor-positive pelvic nodes in 25% vs 55% in the microscopic vs macroscopic groups, respectively (p= 0.10). No risk factors for positive pelvic nodes were identified. For both microscopic and macroscopic disease, addition of an iliac/obturator dissection to an inguinal dissection did not significantly reduce the risk of pelvic nodal recurrence. Five-year overall survival rates for 4 groups were compared: microscopic disease, inguinal dissection alone (72%); microscopic disease, iliac/obturator dissection (68%); macroscopic disease, inguinal dissection alone (51%); and macroscopic disease, iliac/obturator dissection (44%) (p= 0.0163). On survival analysis, addition of an iliac/obturator dissection in either microscopic or macroscopic disease did not affect disease-free survival or regional lymph node recurrence-free survival. The addition of an iliac/obturator dissection to an inguinal dissection for both microscopic and macroscopic nodal disease did not significantly affect lymph node recurrence rates, disease-free survival, or overall survival.