Background  Actinic keratoses (AKs) are epidermal skin lesions with the potential to develop into invasive squamous cell carcinoma (SCC). Treatment at an early stage may prevent development of SCC. Current treatment options are highly destructive and associated with significant side-effects. Early studies with topical diclofenac were encouraging and led to its evaluation for the treatment of actininic keratosis. Previous studies have demonstrated that 3% diclofenac in 2.5% hyaluronan gel is effective and well tolerated in the treatment of AK. The present study was designed to further explore the therapeutic potential of this gel.

Methods  This randomized, double-blind, placebo-controlled trial involved outpatients with a diagnosis of five or more AK lesions contained in one to three 5 cm2 blocks. Patients received either active treatment (3% diclofenac gel in 2.5% hyaluronan gel) or inactive gel vehicle (hyaluronan) as placebo (0.5 g b.i.d. in each 5 cm2 treatment area for 90 days). Assessments included the Target Lesion Number Score (TLNS), Cumulative Lesion Number Score (CLNS), and Global Improvement Indices rated separately by both the investigator (IGII) and patient (PGII).

Results  Results obtained from 96 patients at follow up (30 days after end of treatment) indicated that a significantly higher proportion of patients who received active treatment had a TLNS = 0 compared to the placebo group (50% vs. 20%; P < 0.001). There was also a significant difference between the two groups in CLNS, with 47% of patients in the active treatment group having a CLNS = 0 compared with only 19% in the placebo group (P < 0.001). The proportion of patients with an IGII score of 4 (completely improved) at follow-up was 47% in the active treatment group compared with only 19% in the placebo group (P < 0.001); for PGII these values were 41% vs. 17%, P < 0.001. Both treatments were well tolerated, with most adverse events related to the skin.

Conclusions  Topical 3% diclofenac in 2.5% hyaluronan gel was effective and well tolerated for the treatment of AK.