Outcome analysis for melanoma patients undergoing deep pelvic lymph node dissection

8514 Background: The benefits of deep pelvic lymph node dissection (DLND) for node-positive melanoma patients continue to be debated. The objective of our analysis was to assess factors associated with metastatic disease to deep pelvic nodes and examine survival outcomes following DLND. Methods: We retrospectively reviewed the records of 804 patients undergoing lymph node dissection (1990-2001). 97 patients underwent a superficial inguinofemoral lymph node dissection along with a DLND for indications which included: suspicious radiologic imaging (n= 31), documented superficial disease and concern for deep involvement (n = 57), and in-transit disease undergoing limb perfusion (n=9). Logistic regression was performed to identify factors associated with the metastatic tumor spread to deep nodes. Associations between clinicopathologic factors and disease-specific survival (DSS) were estimated using the Cox proportional hazards model. Results: Fifty-four patients (56%) had metastatic disease (median 2 positive lymph nodes, range 1–12) within their deep pelvis. With a median follow-up of 7.5 years, the 5-year DSS was 42% for patients with positive deep pelvic nodes and 52% for those with negative deep pelvic nodes (p = 0.07). When the number of metastatic deep nodes was stratified, the 5-year DSS for patients with 1 positive node, 2–3 positive nodes, and >3 positive nodes was 49%, 48%, and 27%, respectively (p = 0.04). Age ≥ 50 years (odds ratio [OR] = 3.5, p = 0.03), increasing number of positive superficial nodes (OR = 2.1, p < 0.001), and suspicious findings on pelvic CT images (OR = 11.9, p < 0.001) were associated with metastatic deep nodes. In the multivariate analysis, the number of positive deep nodes (hazard ratio [HR] = 1.1, p = 0.03), male gender (HR = 1.9, p = 0.03), and extra-capsular nodal extension of tumor (HR = 2.7, p < 0.001) were identified as adverse prognostic factors for DSS. Conclusions: Survival outcomes in patients with melanoma metastatic to ≤ 3 deep pelvic lymph nodes are comparable to those in patients without deep nodal involvement. These favorable outcomes support an aggressive surgical approach (i.e., DLND) in patients ≥ 50 years, with multiple positive superficial nodes, and suspicious CT findings. No significant financial relationships to disclose.