Long-term Recurrence after Curettage ± Electrodesiccation for Basal Cell Carcinoma: A Nationwide Cohort Study of 47,358 Tumours from Dermatology Practices

Abstract

The incidence of basal cell carcinoma is increasing globally, with Denmark showing a 220% rise between 2013 and 2021, underscoring the need to optimize treatment strategies. Curettage with or without electrodesiccation (C±E) is commonly used, yet updated tumour-specific recurrence data are limited. Using the Danish Skin Cancer Registry, we assessed long-term recurrence after C±E for 47,358 basal cell carcinomas treated in office-based dermatological practices between 2013 and 2022. Follow-up began one year after treatment, and recurrence was evaluated using Kaplan-Meier analysis and Cox regression to estimate cumulative recurrence rates and hazard ratios (HR) by tumour characteristics. The 5-year recurrence rate was 9.9% (95% CI 9.4-10.3), increasing to 13.3% (12.6-14.1) at 8 years. Head and neck tumours had the highest recurrence (25.1% at 8 years; HR 2.25, 2.00-2.53), as did tumours >10 mm (16.7% at 8 years; HR 1.80, 1.62-1.99), while superficial basal cell carcinomas had the lowest recurrence (8.4% at 8 years; HR 0.46, 0.38-0.56). Incomplete follow-up may have introduced bias in recurrence estimates. This nationwide study, the largest to date with up to 8 years of follow-up, shows that C±E remains a viable treatment, but careful tumour selection is essential to optimize long-term outcomes.