Complications and outcomes following inguinal lymphadenectomy for malignant melanoma in an Asian population.

Purpose: Melanoma is a potentially fatal cutaneous malignancy and regional lymph node (LN) metastases are the most important predictors of mortality. This study aimed to analyze clinical features and risk factors of complications associated with inguinal LN dissection (LND) to establish treatment protocols.

Methods: This single-center retrospective study (2000 to 2018) consisted of patients who underwent inguinal area sentinel LN biopsy (SLNB) or LND due to malignant melanoma. Risk factors and outcomes were analyzed.

Results: One hundred patients underwent SLNB alone (n=67; patients with negative SLNB), complete LND (CLND) after positive SLNB (n=19), or radical LND without SLNB (n=14). Five-year overall survival and disease-free survival rates among these groups were 87.3%, 57.4%, and 61.9%, and 59.0%, 22.7%, and 28.1%, respectively. The complication rate in the SLNB alone group was lower than the other groups (22.4% vs. 47.4% and 35.7%, respectively; P=0.048). Seroma was the most common complication in the SLNB alone group (15.0%); lymphedema was most common in the CLND after SLNB group (21.1%). Multivariate analysis of risk factors for postoperative complications found the hazard ratio for body mass index >28 kg/m² was 4.376 (95% confidence interval [CI], 1.243-15.401; P=0.022). The hazard ratio for LND (including CLND after SLNB and radical LND without SLNB) was 3.263 (95% CI, 1.248-8.529; P=0.016).

Conclusion: Inguinal LND is a higher risk procedure compared to SLNB and other sites for postoperative complications, irrespective of meticulous surgical techniques. More studies are needed to establish treatment protocols (e.g., observation vs. CLND after a positive SLNB result) and the risks and benefits in Asian populations.