Background <p>Regional lymph nodes are a common first site of metastasis in patients diagnosed with invasive melanoma. Knowledge of sentinel lymph node status provides strong prognostic information in melanoma and is important for staging and treatment decisions. The National Comprehensive Cancer Network^® (NCCN) recommends performance of sentinel lymph node biopsy (SLNB) for melanoma patients with a T category of ≥T2a. This study aims to assess our academic institution’s guideline adherence to improve quality of care.</p> Methods <p>Retrospective review of medical records from 2017 to 2023 identified 628 patients referred to our institution for invasive melanoma treatment. Adherence to guidelines was assessed using Chi-square analyses and Fisher’s exact tests.</p> Results <p>In total, 8.2% of cases did not follow the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines^®) for SLNB. When justification provided within the medical record was considered adherent to guidelines, our rate of discordance was 1.6%. Head and neck melanomas were more likely to have guideline-discordant SLNB management, regardless of whether or not a justification was provided.</p> Conclusion <p>Greater than 98% of melanoma cases at our institution aligned with the SLNB NCCN Guidelines^®. We outlined the complex justifications physicians and patients may use to pursue care that is nonadherent to guidelines. Employment of SLNB may be limited by medical comorbidities, surgical risks, and when the management would not change based on the result. Our study provides a blueprint for institutional assessment of guideline adherence and highlights the importance of documentation and guideline dissemination.</p>