A 12-month follow-up split-scalp study comparing calcipotriol-assisted MAL-PDT with conventional MAL-PDT for the treatment of actinic keratosis: a randomized controlled trial

To enhance the efficacy of photodynamic therapy (PDT) for actinic keratosis (AKs), physical and chemical pre-treatments, such as calcipotriol (CAL) have been suggested. To compare the long-term 12-month efficacy and safety between methylaminolevulinate (MAL)-PDT and prior application of topical CAL versus conventional MAL-PDT for AKs of the scalp. Twenty patients with multiple AKs on the scalp were randomized to receive conventional PDT on one side of the scalp and CAL-assisted PDT, in which CAL was applied daily for 15 days beforehand, on the other side. Patients were evaluated for AK clearance at three, six and 12 months thereafter. All 20 patients completed the study. At three months, overall AK clearance was 92.07% and 82.04% for CAL-PDT and conventional PDT, respectively (p < 0.001). Similar results were found at six and 12 months: 92.07% and 81.69% (p < 0.001), and 90.69% and 77.46% (p < 0.001) for CAL-PDT and conventional PDT, respectively. Grade I AKs showed a similar response rate for both sides (p = 0.055) at three months and significant differences were obtained at six (p = 0.001) and 12 months (p < 0.001) for CAL-PDT and conventional PDT. Grade II AKs showed greater improvement on the CAL-PDT side (89.55% vs 62.90%) (p < 0.001) at three months. No difference was found at six and 12 months. CAL-PDT proved to be safe and more effective than conventional PDT for the treatment of AKs on the scalp after 12 months. CAL pre-treatment may have enhanced the efficacy of PDT for AK treatment, however, larger trials are needed to corroborate our findings.