BSV03 Vulval melanoma: a case series and audit from a UK tertiary referral centre

Abstract

Vulvovaginal mucosal melanomas (VVMMs) affect 1.6 individuals per million per year. Patients frequently present with advanced disease and have poor outcomes. As VVMMs are rare, there is a paucity of high-quality evidence on which to base treatment strategies. This study aimed to describe the clinical course and outcomes for patients diagnosed with VVMM and audit the service provided in our tertiary referral centre. In total, 18 cases of VVMM were identified from 358 records of patients diagnosed with vulvovaginal cancer between January 2015 and September 2025. Treatment course and patient outcomes were compared with standards set out by Melanoma Focus for ano-uro-genital mucosal melanoma. Fifteen patients (83%) were first assessed in a gynaecology urgent suspected cancer clinic, and 15 (83%) underwent a diagnostic biopsy prior to surgical resection. Seventeen (94%) had invasive disease at presentation and 50% had an initial Breslow thickness ≥ 4 mm. Overall, 78% had features of both melanoma in situ and invasive disease. Lateral margins following excision were involved in 53%, predominantly with in situ disease. When next-generation sequencing was performed, KIT mutations were identified in 17% (n = 2). Most patients underwent staging investigations including computed tomography (CT) of the thorax, abdomen and pelvis, and CT of the head (93%). Adjuvant treatments included dacarbazine chemotherapy (n = 1), radiotherapy (n = 3) and immunotherapy (n = 8). Five (28%) of the 18 patients were deceased at the point of data collection. One-quarter of patients (2 of 8, 25%) who received immunotherapy did not survive, compared with 30% (3 of 10) who did not receive immunotherapy; treatment was frequently limited by adverse effects. No patients underwent formal assessment of the impact of VVMM on their quality of life. This study highlights the critical need for further research into optimal management strategies for VVMM, particularly the impact of molecular profiles and relevance of immunotherapy. Studies into the impact of VVMM on quality of life are urgently required. Our team have developed a local standard operating procedure to improve patient management.