Treatment of actinic keratoses on the dorsum of the hands: ALA-PDT versus diclofenac 3% gel followed by ALA-PDT. A placebo-controlled, double-blind, pilot study

Background: Actinic keratoses (AK) are sun-induced epithelial skin lesions, which are at risk to progress to squamous cell carcinoma. One of the treatments of AK is photodynamic therapy (PDT), which often has to be repeated. Another treatment for these lesions is diclofenac 3% gel. Although both treatments have shown to be effective, they have never been studied together. Objective: To investigate whether a pre-treatment of AK on the dorsum of the hands with diclofenac 3% gel improves the efficacy of PDT. Methods: In this placebo-controlled, randomized, double-blind, pilot study with 10 patients, both hands were pre-treated – one with diclofenac gel and the other with placebo gel – and then the hands were treated with ALA-PDT. Total lesion number scores, total thickness scores and global improvement scores were used to assess efficacy. Pain scores were recorded during PDT. Results: In both groups, the number of lesions significantly decreased. At 12 months' follow-up, significantly fewer AK were seen in the diclofenac group. Total lesion thickness scores decreased significantly in both groups. Pain during PDT was greater in the diclofenac group. Conclusions: Both treatments are effective in treating AK. A pre-treatment with diclofenac gel seems to result in fewer AK at 12 months' follow-up, compared to placebo. Side effects were worse when using the active drug.