Objective: To compare the efficacy, tolerability, and cosmetic outcome of photodynamic therapy (PDT) using topical methyl aminolevulinate with cryotherapy or topical fluorouracil for treatment of squamous cell carcinoma in situ.
Design: Randomized, placebo-controlled study, with follow-up at 3 and 12 months after last treatment.
Setting: Forty outpatient dermatology centers in 11 European countries.
Patients: Random sample of 225 patients with histologically confirmed squamous cell carcinoma in situ (lesion size, 6-40 mm) and no evidence of progression.
Interventions: Treatment with PDT with methyl aminolevulinate (160 mg/g; n = 96) or matching placebo cream (n = 17), cryotherapy (n = 82), or topical fluorouracil (5% cream; n = 30). Methyl aminolevulinate or placebo cream was applied for 3 hours before illumination with broadband red light (75 J/cm2, 570-670 nm). Treatment was repeated 1 week later. Cryotherapy was performed with liquid nitrogen spray. Fluorouracil was applied for 4 weeks. Lesions with a partial response at 3 months were re-treated.
Main outcome measures: Clinically verified complete response of lesions; blinded and on-site assessment of cosmetic outcome (4-point rating scale).
Results: At 12 months, the estimated sustained lesion complete response rate with methyl aminolevulinate PDT was superior to that with cryotherapy (80% vs 67%; odds ratio, 1.77; 95% confidence interval, 1.01-3.12; P = .047), and better than that with fluorouracil (80% vs 69%; odds ratio, 1.64; 95% confidence interval, 0.78-3.45; P = .19). Cosmetic outcome at 3 months was good or excellent in 94% of patients treated with methyl aminolevulinate PDT vs 66% with cryotherapy and 76% with fluorouracil, and was maintained at 12 months.
Conclusion: Methyl aminolevulinate PDT is an effective treatment option for squamous cell carcinoma in situ, with excellent cosmesis.