P148 Recurrence rates and follow-up outcomes of pleomorphic dermal sarcomas across three dermatology departments: results of an audit against the UK guidelines for the management of soft-tissue sarcomas 2016–2024

Abstract Pleomorphic dermal sarcoma (PDS) is a rare skin cancer that displays an aggressive growth pattern. An estimated 17% of cases demonstrate local recurrence and 16% show distant metastases (Ørholt M, Abebe K, Rasmussen LE et al., Atypical fibroxanthoma and pleomorphic dermal sarcoma: local recurrence and metastasis in a nationwide population-based cohort of 1118 patients. J Am Acad Dermatol 2023; 89: 1177–84). There is no consensus on the management and follow-up approach locally. UK guidelines on the management of soft-tissue sarcomas in 2016 and 2024 acknowledge the lack of universal agreement on resection margins but have outlined a follow-up schedule for primary disease (Hayes AJ, Nixon IF, Strauss DC et al. UK guidelines for the management of soft tissue sarcomas. Br J Cancer 2025; 132: 11–31). The aim of this multicentre audit was to improve patient safety by establishing a consensus-based follow-up schedule for patients diagnosed with PDS, as well as highlighting trends and differences in management. For each centre patients were identified with a diagnosis of PDS made up to 5 years earlier to allow for a follow-up period. Characteristics of the primary tumour, all treatments received and incidences of recurrence or metastasis were recorded. Follow-up schedules were compared against the current UK guideline. Fifty cases of PDS were identified; analysis showed a wide variation in management and follow-up, both within and between centres. At one centre with 22 patients, the mean age at diagnosis was 79.5 years (range 59–97), and the majority of PDS diagnoses were located on the head and neck (17 of 22). Four of 22 patients had 5-year follow-up and 4 of 22 had staging investigations. Only 3 of 22 cases had a tumour histological grade stated, which made risk stratifying challenging. At the time of submission, the results from the other two centres are undergoing final analysis ready for publication. This project has demonstrated huge heterogeneity in the management and follow-up of these high-risk tumours. Good practice was identified in each centre, but there were several areas where improvements could be made, which would be guided best by a UK-wide guideline for PDS management. We present this evidence to support the need for a standardized approach to PDS management, focusing on a uniform approach to histopathological reporting, recommended staging investigations and defined follow-up frequency and period. In lieu of specific PDS guidelines we would currently suggest that current UK guidelines are followed, until our data are used to help categorize the key criteria for best practice management of patients with PDS.