A Randomized Trial of Broad Area ALA–PDT for Field Cancerization Mitigation in High-Risk Patients

Background: The relationship between actinic keratoses (AKs) and nonmelanoma skin cancers (NMSCs) is well established. Patients with field cancerization are at high risk of developing new lesions. A treatment to interrupt new lesion formation or progression is required. Objective: To evaluate occurrence of AKs in high-risk patients after field aminolevulinic acid–photodynamic therapy (ALA–PDT). Methods: In this randomized, parallel-group, evaluator-blinded, 52-week study, patients with 4–15 facial AKs (N = 166) were random-ized (ALA 2x vs ALA 3x vs vehicle [VEH]-pooled [VEH 2x+VEH 3x], 1:1:1) to receive 2 or 3 PDT treatments (1-hour incubation) following cryotherapy at screening. Results: More ALA-treated patients than VEH-treated patients had no AKs at week 52 (ALA 2x, 36.0%, P=0.0102; ALA 3x, 37.5%, P=0.0089; VEH, 18.9%). Week 52 lesion recurrence rates were 7.7% (P=0.0004) and 6.1% (P<0.0001) for ALA 2x and ALA 3x, respec-tively, versus 15.5% for VEH. Therapy was well tolerated; no patient requested early termination of light treatment. ALA 3x reduced NMSC development versus VEH (5 vs 12 lesions, P=0.0014). Conclusion: 2 or 3 ALA–PDT treatments with 1-hour incubation can significantly reduce occurrence of AKs after 1 year in patients at high risk of NMSC versus VEH–PDT (NCT02239679). J Drugs Dermatol. 2020;19(5):452-458. doi:10.36849/JDD.2020.4930