216 Sentinel Lymph Node Biopsies for Malignant Melanoma – a Single Centre, Closed-Loop Audit

Abstract

Abstract Aim Sentinel Lymph Node Biopsy (SLNB) has been used as staging tool for Malignant Melanoma (MM) for over 15 years. This audit sought to ensure that standards of care are being met in melanoma patients undergoing SLNB at the Royal Free Hospital (RFH). Method A retrospective audit examined electronic notes for patients undergoing SLNB for MM at RFH March-September 2021 (Loop 1, n = 139) and September 2021-March 2022 (Loop 2, n = 100). The standard used to determine eligibility for SLNB originated from a UK consensus statement recommending SLNB in primary cutaneous melanoma ≥pT2a or pT1b and either lymphovascular invasion or a mitotic rate ≥2/mm2. Results In Loop 1 of the audit, 6.5% of patients undergoing SLNB (n = 9) did not meet the criteria. A further 4.3% (n = 6) did not have documented lymphovascular invasion or mitotic index and, therefore, potentially also did not meet criteria. Between loops 1 and 2, standard referral letters were disseminated to referring sites, who were also instructed to include full histology reports with referrals. In Loop 2 of the audit, 3% of patients undergoing SLNB (n = 3) did not meet the criteria. A further 11% (n = 11) did not have a documented lymphovascular invasion or mitotic index in the referral and, therefore, potentially also did not meet criteria. Conclusions SLNB carried out on non-eligible patients carries risks of increased morbidity and mortality. Interventions implemented between loops 1 and 2 in our single-centre audit did not lead to sustained change and highlight the need for further research and improvements.