Evaluation of residual tumour in wide local excision for melanoma: A nationwide population-based study

Background: Melanoma incidence is increasing, emphasizing the need for optimized management. Wide local excision (WLE) remains the standard for locoregional disease control. The main advantage of WLE is likely in removing microsatellite lesions near the primary tumour if fully excised. This study evaluates the incidence of residual tumour in WLE specimens using a large nationwide cohort. This to refine patient selection and support a more evidence-based approach to surgical management Methods: A nationwide, population-based study was conducted using data from the Dutch Pathology Databank. Patients diagnosed with melanoma between 2000 and 2023 who had a completely resected tumour with diagnostic excision without reported microsatellite lesions. Results: Among 44,628 patients undergoing WLE, 2.1 % had residual tumour. Residual tumour was significantly correlated with increased Breslow thickness, ulceration and nodular melanoma subtype. The incidence of residual tumour increased with advancing T stage, from 1.2 % in Tis to 11.2 % in T4b melanomas. Conclusion: The incidence of residual tumour following WLE for melanomas up to T2 is low (< 3 %). Our findings suggest that omission of the WLE for all melanomas up to T2 may well be considered.