DS25 A survey study of management of melanoma in situ and lentigo maligna in the UK

Abstract

Melanoma in situ (MIS) is characterized by malignant melanocytes confined to the epidermis and most commonly presents as lentigo maligna (LM) or superficial spreading MIS (SSMIS). Despite rising incidence, management remains inconsistent, particularly regarding excision margins, re-excision, nonsurgical therapies and follow-up. Ongoing debate reflects concerns about overtreatment and uncertainty surrounding progression risk. The aim of this study was to evaluate contemporary UK practice in the management of MIS and LM and to identify areas of clinical variation and uncertainty. A cross-sectional electronic survey was distributed between July and September 2025 to UK clinicians managing MIS via national dermatology societies. The 13-item questionnaire explored diagnostic approaches, treatment strategies, topical therapies, follow-up practices and experience of recurrence and metastasis. In total, 118 clinicians responded, predominantly consultant dermatologists (84.8%). Diagnostic excision with 1–2-mm margins was standard for trunk and limb lesions (87.8%). Multidisciplinary discussion was routine for MIS (74%) and LM (78%). Following diagnostic excision of MIS with 2-mm margins, 55.6% routinely recommended wide local excision (WLE) to 5 mm irrespectively of histological clearance, while others favoured selective re-excision. For facial LM, 53% routinely offered 5-mm WLE, frequently individualizing management according to patient and lesion factors. Standard excision was the preferred first-line treatment for biopsy-confirmed LM (80%), although imiquimod, staged excision and observation were commonly used in frail or high-risk patients; 60% prescribed imiquimod within the preceding year. Follow-up practices varied widely, with most discharging patients after treatment completion. Local recurrence had been observed by 16% for MIS and 38% for LM, while metastasis was rare. Clearer national guidance was requested by 83%. Management of MIS and LM in the UK is hetero­geneous, highlighting variation in re-excision, topical therapy, follow-up and national guidance. This variation informs the need for consensus through clearer national guidance based on current evidence and the need for robust randomized trials assessing outcomes.