Sequential treatment with calcitriol and methyl aminolevulinate-daylight photodynamic therapy for patients with multiple actinic keratoses of the upper extremities

•Overall lesion response rate was higher for CAL-DL-PDT than for P-DL-PDT at 3 months.•Similar results were obtained for grade I AKs with both treatment regimens.•Lesions response rate of grouped AK II/III was significantly higher for CAL-DL-PDT than for P-DL-PDT.•No difference was observed in pain intensity between treatments; local skin reactions were more frequent with CAL-DL-PDT.•Overall subject’s preference was slightly significantly in favor of P-DL-PDT. Topical photodynamic therapy (PDT) is a widely used and effective treatment for actinic keratoses (AKs). However, cure rates are significantly reduced for AKs on acral sites. We compared the sequential regimen of topical calcitriol and methyl aminolevulinate (MAL) daylight-PDT (CAL-DL-PDT) versus placebo and MAL-DL-PDT (P-DL-PDT) on acral AKs in an intra-individual, randomized trial. Adult patients with multiple all grade AKs of the upper extremities were treated with daily topical calcitriol or placebo for 14 days followed by 2 sessions of DL-MAL-PDT. After 3 months, patients were evaluated for lesion response rate, both overall and by AK grade, and patient ≥ 75 % clearance rate. Safety assessments included pain VAS immediately after the first DL-PDT session, side effects after calcitriol pretreatment and 7 days after the first DL-PDT session. Cosmetic outcome by the physician and patient’s preference were graded at the end of the study. Forty-two patients were enrolled and 36/42 completed the study. After 3 months, the overall lesion response rate and patient ≥ 75 % clearance rate of CAL-DL-PDT were higher, albeit not significantly, than P-DL-PDT. According to grade, response rate of grouped AK II/III was significantly higher for CAL-DL-PDT than for P-DL-PDT while similar results were observed for grade I AKs. Mild erythema and itch were reported after calcitriol application. No significant difference was observed in pain intensity. Local skin reactions occurred more frequently on the CAL-DL-PDT-treated sides. Cosmetic outcome did not differ but overall subject’s preference was slightly significantly in favor of P-DL-PDT. CAL-DL-PDT is more effective than P-DL-PDT for thicker “difficult to treat” AKs on the upper extremities but is associated with increased local skin reactions.