Actinic keratoses are sun-induced premalignant lesions that occur more commonly in older or immunosuppressed persons, males and people with fair skin. Untreated lesions can develop into squamous cell carcinoma. Current treatments such as cryotherapy, curettage or topical treatment with fluorouracil have the potential to cause considerable discomfort and are poorly tolerated. A number of nonsteroidal anti-inflammatory drugs (NSAIDs) have been found to affect the growth profile of some tumors and may offer potential benefit for the treatment of actinic keratoses. As the geriatric population in the United States increases, the prevalence of these lesions will probably continue to increase. Rivers and McLean performed an open-label study of topical 3 percent diclofenac in 2.5 percent hyaluronic acid gel to determine its effectiveness in the treatment of actinic keratoses.
Study participants were instructed to apply 1 g of the gel to one or more actinic keratoses twice daily for as many as 180 days. A total of 29 adults were treated for periods of 33 to 176 days and were assessed by both visual and photographic methods. Twenty-seven patients were reevaluated 30 days after they discontinued using the gel. Of the 27 patients, 22 (81 percent) had a complete response, and another four (15 percent) showed marked clinical improvement. Thirty days later, results were more dramatic, with a nearly complete response in all subjects. In the 22 patients whose lesion response was considered complete, the mean time to complete resolution was 94 days.
When study participants assessed the efficacy of the gel after treatment was discontinued, 45 percent thought the results were excellent, 10 percent rated the results as good, 10 percent rated the results as fair and 34 percent thought the results were poor. After the study was completed, the tubes of gel were weighed to assess compliance. Approximately 50 percent less gel was used than expected. Ten study participants were found to have used more than the 1 g per day recommended, and 14 participants had used less than 1 g daily.
The only clinically relevant adverse effects were those related to skin irritation, which occurred in 21 patients (72 percent). In the seven patients who experienced irritant contact dermatitis at the treatment site, the drug was discontinued and the reaction resolved within one to two weeks. On provocative testing, the eczematous reaction appeared to be irritant rather than allergic in nature.
Topical 3 percent diclofenac in 2.5 percent hyaluronic acid gel was highly effective in reducing or completely eliminating the actinic lesions. Lesions continued to improve even after treatment ceased. Thirty days after treatment, the lesions were considered clinically clear in 81 percent of the patients.
The authors conclude that 3 percent diclofenac in 2.5 percent hyaluronic acid gel has promise as a first-line topical therapy in the treatment of patients with actinic keratoses and should be compared with other commonly used NSAIDs in prospective trials.