5-Fluorouracil and MAL-PDT vs Surgery for Bowen's Disease: 4-Year Outcomes

BACKGROUND: Evidence on long-term efficacy with head-to-head comparison of different treatments for Bowen's disease (BD) is lacking. OBJECTIVE: To compare the long-term efficacy of 5-fluorouracil and methylaminolevulinate photodynamic therapy (MAL-PDT) versus surgical excision (SE) in BD. METHODS: In this multicenter, non-inferiority randomized controlled trial, 250 patients with BD were invited for long-term follow-up, 3 to 5 years post-treatment. Patients had been randomly assigned to 5FU, MAL-PDT, or SE in a 1:1:1-ratio. The primary outcome was the cumulative probability of tumor-free survival 4 years post-treatment with treatment failures confirmed histopathologically. A secondary endpoint was the risk of cutaneous squamous cell carcinoma (cSCC). RESULTS: During the first year of follow-up, treatment failure was observed in 27 patients. During long-term follow-up, only 1 additional patient developed a recurrence, 5 years after MAL-PDT. The 4-year cumulative probability of tumor-free survival was 97.5% for SE (95% confidence interval (CI) 90.4-99.4), 86.2% for 5FU (95% CI 76.4-92.1), and 82.7% for MAL-PDT (95% CI 72.6-89.4). No patient developed a cSCC in the treated area. LIMITATIONS: Loss to follow-up occurred in 23.2% of patients. CONCLUSIONS: During long-term follow-up, the additional risk of recurrence of BD after 5FU and SE, and the risk of developing a cSCC from a treated BD were negligible. Treatment with 5FU remains non-inferior to SE, whereas non-inferiority of MAL-PDT could not be concluded.