Background: Block dissection of the inguinal lymph nodes is the routine management for palpable metastatic melanoma confined to this node basin. Involvement of the next tier external iliac and obturator lymph nodes in the pelvis is common, and untreated pelvic nodal disease can become advanced before becoming clinically apparent. We have routinely performed combined inguinal and pelvic (ilioinguinal) lymph node block dissection to avoid this morbid outcome.
Methods: A retrospective analysis of all patients undergoing ilioinguinal lymph node dissection for melanoma between January 1998 and January 2006 was carried out.
Results: There were 72 patients with a median age of 52.7 years (19.7-75.2 years) who were followed up for a median of 28.9 months (1.0-115.0 months) after ilioinguinal lymph node dissection. There were 22 (30.6%) of 72 patients with histologically involved pelvic lymph nodes. Preoperative computed tomography (CT) scanning accuracy for pelvic lymph node involvement was as follows: sensitivity 60.0%, specificity 100.0%, positive predictive value 100.0% and negative predictive value 86.2%. Lymphoedema was reported in 32 (44.4%) of 72 patients. Median time to first recurrence was 8.7 months (0.8-69.7 months). Regional recurrence occurred in 6 (8.3%) of 72 patients at a median of 4.9 months (0.9-32.0 months). Extranodal spread was the only factor adversely associated with disease-free survival. In all patients, 5-year disease-free survival was 38% (95% confidence interval (CI) 26-50) and overall survival 47% (95% CI 33-60).
Conclusion: Palpable metastatic melanoma in the groin is commonly associated with pelvic lymph node involvement, is not well predicted by CT scanning and is appropriately managed by ilioinguinal lymph node block dissection.