Surgical excision versus topical 5% 5-fluorouracil and photodynamic therapy in treatment of Bowen's disease: A multicenter randomized controlled trial.

BACKGROUND: Randomized controlled trials comparing the effectiveness of 5-fluorouracil cream, methylaminolevulinate photodynamic therapy (MAL-PDT) and surgical excision in patients with Bowen's disease are lacking. METHODS: In this multicenter noninferiority trial, patients with a histologically proven Bowen's disease of 4-40 mm were randomly assigned to excision with 5 mm margin, 5% 5-fluorouracil cream twice daily for 4 weeks, or 2 sessions of MAL-PDT with 1 week interval. The primary outcome was the proportion of patients with sustained clearance at 12 months after treatment. A noninferiority margin of 22% was used. RESULTS: Between May 2019 and January 2021, 250 patients were randomized. The proportion of patients with sustained clearance was 97.4% (75/77) after excision, 85.7% (66/77) after 5-fluorouracil, and 82.1% (64/78) after MAL-PDT. Absolute differences were -11.7% (95% CI -18.9 to -4.5; P = .0049) for 5-fluorouracil versus excision and -15.4% (95% CI -23.1 to -7.6; P = .00078) for MAL-PDT versus excision. Both noninvasive treatments significantly more often led to good or excellent cosmetic outcome. CONCLUSIONS: Based on our predefined noninferiority margin of 22%, 5-fluorourcail is noninferior to excision and associated with better cosmetic outcome. For MAL-PDT noninferiority to excision cannot be concluded. Therefore, 5-fluorouracil should be preferred over excision and MAL-PDT in treatment of Bowen's disease.

Risk of Invasive Cutaneous Squamous Cell Carcinoma After Different Treatments for Actinic Keratosis: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Treatment of actinic keratosis (AK) aims to prevent cutaneous squamous cell carcinoma (cSCC). However, whether AK can progress into invasive cSCC is a matter of debate, and little is known about the effect of treatment on preventing cSCC. Objectives: To evaluate the risk of invasive cSCC and factors that may contribute to increased risk in patients with multiple AKs. Design, Setting, and Participants: In this secondary analysis of a multicenter randomized clinical trial, 624 patients with a minimum of 5 AKs within an area of 25 to 100 cm2 on the head were recruited from the Department of Dermatology of 4 hospitals in the Netherlands. Long-term follow-up was performed from July 1, 2019, to December 31, 2020. Interventions: Patients were randomized to treatment with 5% fluorouracil, 5% imiquimod cream, methylaminolevulinate photodynamic therapy, or 0.015% ingenol mebutate gel. Main Outcomes and Measures: The primary outcome was the proportion of patients with invasive cSCC in the target area during follow-up. Secondary outcomes were the associations between risk of invasive cSCC and a priori defined potential prognostic factors, including type of treatment, severity of AK (Olsen grade), history of nonmelanoma skin cancer, and additional treatment. Results: Of the 624 patients (558 [89.4%] male; median age, 73 years [range, 48-94 years]) in the study, 26 were diagnosed with a histologically proven invasive cSCC in the target area during follow-up. The total 4-year risk of developing cSCC in a previously treated area of AK was 3.7% (95% CI, 2.4%-5.7%), varying from 2.2% (95% CI, 0.7%-6.6%) in patients treated with fluorouracil to 5.8% (95% CI, 2.9%-11.3%) in patients treated with imiquimod. In patients with severe AK (Olsen grade III), the risk was 20.9% (95% CI, 10.8%-38.1%), and the risk was especially high (33.5%; 95% CI, 18.2%-56.3%) in patients with severe AK who needed additional treatment. Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, risk of invasive cSCC was highest in patients with Olsen grade III AK and was substantially increased in patients who received additional treatment. These patients should be closely followed up after treatment. Trial Registration: ClinicalTrials.gov Identifier: NCT02281682.