612 Sentinel Lymph Node Biopsy for Patients with Cutaneous Malignant Melanoma. an Audit of the First 30 Months of a New Regional Service

Abstract Aim In this region, the Sentinel Lymph Node Biopsy (SLNB) Service was established in 2018 and suspended in 2020, due to the COVID-19 pandemic. Service has resumed under interim criteria, accounting for COVID-19 constraints. Patients not fulfilling these criteria (SLNB for tumour stage pT3a or greater) had wide local excision (WLE) alone. This audit aims to examine quality of Service delivery to date, plan full-Service resumption, and generate a cohort for ongoing outcomes research. Method A prospectively collected database captured patients with tumour stage pT1b or higher. Data were analysed for demographics, tumour characteristics and outcome of Service referral, and compared to predetermined performance indicators. Results Data were collected on 410 patients, from December 2018 to April 2021; 94.4% had complete datasets. Of the remaining 5.6%, none underwent SLNB. The mean age was 62 (range 12–96). 187 patients were male; 220 were female. The most frequent tumour location in males was the trunk (36.0%), differing from females (41.8% lower limb). The most common tumour stage was pT2a, occurring in 34.7% (27.9% males, 40.7% females). 141 eligible patients were investigated with SLNB (18.4% positive, 75.9% negative, 5.7% failed). 7.9% were unsuitable for SLNB and 4.5% declined. The remaining 168 patients did not fulfil interim criteria for SLNB and underwent WLE. Conclusions This audit assesses Service quality and will be used to facilitate full-Service provision. Interim criteria reflect a higher rate of positive SLNB. Ongoing research investigates the rate of false negative SLNB and impact of the COVID-19 pandemic on rates of recurrent/disseminated disease.