Impact of National Comprehensive Cancer Network Guidelines on Case Selection and Outcomes for Sentinel Lymph Node Biopsy in Thin Melanoma.

Background: In 2010, the National Comprehensive Cancer Network (NCCN) recommended sentinel lymph node biopsy (SLNB) for thin melanomas ≤1 mm with mitotic rate (MR) ≥1. In 2016, the criteria were changed to Breslow depth >0.75 mm and MR ≥1.

Objective: To compare the impact of 2010 and 2016 NCCN guidelines on SLNB case selection and thin melanoma outcomes.

Methods: Ten-year retrospective cohort of primary thin melanomas at an academic hospital was retroactively stratified for SLNB eligibility using the 2010 and 2016 NCCN guidelines. Nodal recurrence-free survival (NRFS) and disease-free survival (DFS) were compared.

Results: Eight hundred two patients with 859 tumors and median follow-up of 79 months were included. Eleven percent fewer tumors qualified for SLNB under 2016 versus 2010 NCCN guidelines (19% vs 8%, p < .001). The 2016-qualifying cases also had lower 10-year NRFS (70.7% vs 95.2%, p < .001) and DFS (64.7% vs 91.4%, p < .001). Among 2016-qualifying cases, those that received SLNB had improved NRFS (85.6% vs 35.3%, p = .001) and DFS (80.2% vs 30.5%, p < .001) as compared to those that did not receive SLNB.

Conclusions: The 2016 NCCN guidelines reduced the number of thin melanomas qualifying for SLNB and more accurately selected cases with higher risks of nodal recurrence and death.