Abstract
BACKGROUND: Sentinel lymph node biopsy (SLNB) is recommended for patients with >10% risk of metastasis and not for those with <5% risk. The National Comprehensive Cancer Network acknowledges that individualized risk assessment tools, such as the Melanoma Institute of Australia (MIA) sentinel node metastasis risk model, may aid decision-making. We hypothesized that SLNB utilization would not differ substantially between the pre- and post-publication eras of the MIA model. METHODS: We retrospectively reviewed National Cancer Database data from 2018 to 2022. Patients with thin melanomas (<1.0 mm Breslow depth) were classified into <5% or >10% sentinel node positivity risk groups using the MIA model. Demographic and pathologic characteristics were examined. RESULTS: Of 58,119 patients with thin melanomas, 43,551 met inclusion criteria after excluding 14,491 with intermediate (5-10%) risk. Among 3949 with >10% risk, 62.9% had SLNB and 37.1% had SLNB omitted. Conversely, among 39,602 with <5% risk, 13.7% received SLNB. Tumor thickness, ulceration, and mitotic rate were significant predictors of SLNB in both groups. Increasing age was associated with lower odds of SLNB only in the low-risk cohort. Notably, SLNB utilization changed minimally following publication of the MIA model, increasing by <1% in the <5% group and 4% in the >10% group. CONCLUSIONS: Before and after MIA model publication, SLNB was underutilized in high-risk patients and overutilized in low-risk patients. Utilization was primarily driven by tumor-specific factors. Our findings suggest limited early adoption of the model and highlight the need for improved dissemination of personalized risk stratification tools.