Pelvic lymph node dissection is beneficial in subsets of patients with node-positive melanoma

Background: The benefits of deep pelvic lymph node dissection (DLND) for patients with node-positive melanoma continue to be debated. The objective of our analysis was to identify factors associated with involvement of pelvic nodes and to determine survival outcomes following DLND. Methods: We retrospectively reviewed the records of 804 patients who had undergone any type of lymph node dissection between 1990 and 2001. Logistic regression was performed to identify factors associated with tumor metastasis to pelvic nodes. Associations between clinicopathological factors and survival outcomes were estimated using the Cox proportional hazards model. Results: Of the 804 patients, 235 underwent superficial lymph node dissection (SLND) and 97 underwent combined SLND and DLND (combined LND). Age ≥50 years, number of positive superficial nodes, and positive radiological imaging findings were found to be predictors of metastasis to deep nodes. With a median follow-up of 7.5 years, 5-year overall survival (OS) was 42% for patients with positive deep nodes and 51% for those with negative deep nodes (P = 0.11). OS in patients with melanoma that metastasized to three or fewer deep pelvic lymph nodes is comparable to that in patients with no deep nodal involvement. Multivariate analysis identified number of positive deep nodes, male gender, and extra-capsular extension as independent adverse prognostic factors for OS. Conclusions: These relatively favorable survival outcomes support current surgical practice and the classification of metastatic pelvic nodal disease as stage-III rather than stage-IV (distant) disease.