Effect of a 1-week treatment with 0.5% topical fluorouracil on occurrence of actinic keratosis after cryosurgery: a randomized, vehicle-controlled clinical trial.

Background: No long-term randomized controlled clinical trial has compared the efficacy of cryosurgery alone vs cryosurgery following fluorouracil applications for the treatment of actinic keratosis.

Objective: To determine the 6-month outcome of a 1-week course of 0.5% fluorouracil followed by cryosurgery.

Design: Prospective, multicenter, randomized, double-blind, vehicle-controlled clinical trial performed in community and academic outpatient clinics.

Patients: A total of 144 patients with 5 or more visible or palpable actinic keratoses on the face.

Interventions: Topical 0.5% fluorouracil or vehicle once daily for 7 days. At the 4-week follow-up visit, residual lesions were treated with cryosurgery.

Main Outcome Measure: Reduction in facial actinic keratoses from baseline to 4 weeks and 6 months.

Results: At 4 weeks, mean actinic keratosis lesion count was reduced by 62.4% in the 0.5% fluorouracil group vs 28.8% in the vehicle group (P<.001), and complete clearance was achieved in 16.7% of patients in the 0.5% fluorouracil group vs 0% of those in the vehicle group (P<.001). At 6 months, mean lesion count was reduced by 67.0% in the 0.5% fluorouracil plus cryosurgery group vs 45.6% in the vehicle plus cryosurgery group (P =.01), and significantly more patients in the 0.5% fluorouracil plus cryosurgery group than in the vehicle plus cryosurgery group had complete clearance (30% vs 7.7%; P<.001).

Conclusions: A 1-week course of topical 0.5% fluorouracil before cryosurgery is significantly more effective in reducing patients' numbers of actinic keratosis lesions 6 months after treatment than cryosurgery alone. The high occurrence rate of actinic keratosis lesions at 6 months suggests a need for follow-up.