Randomised controlled trials (RCTs) that compared treatment of actinic keratosis using 5-fluorouracil (5-FU) with placebo or another active treatment, or that investigated different 5-FU dosage regimens, were eligible for inclusion. Participants were not required to have a histological diagnosis for inclusion (clinical diagnosis was sufficient).
5-FU was compared to placebo, facial resurfacing with carbon dioxide laser or 30% trichloroacetic acid peel, imiquimod, cryotherapy, diclofenac sodium 3% gel (DFS), 5-aminolevulinic acid (ALA) photodynamic therapy (PDT) (activated with either blue light, red light, or pulsed laser light), 5-FU augmented with tretinoin and placebo. Most included studies used 5% 5-FU; other studies used 0.5% 5-FU. One study compared different 5-FU regimes. Duration of interventions ranged from one week to 16 weeks. Participants in most of the included studies had actinic keratosis lesions on the face or scalp. Mean number of lesions (where given) ranged from more than three to 17.5. Mean age ranged from 62 to 73 years. The proportion of males ranged from 47% to 95%.
Eligible outcomes were not specified, but the outcomes measured included absolute and proportional changes in lesions counts per patient, changes in total lesion count, change in lesion area, tolerability, and patient preferences. The authors considered that complete healing of lesions treated with 5-FU required two months after cessation of treatment, but assessment was short (four weeks) in half the included RCTs.
Two independent researchers performed the study selection. The authors did not state how disagreements were resolved.