Daylight Photodynamic Therapy of Actinic Keratosis Without Curettage is As Effective As with Curettage: a Randomized Clinical Trial

Background: Guidelines for photodynamic therapy (PDT) of actinic keratosis (AK) recommend pretreatment with curettage. The impact of curettage on cure rate is, however, not well established.

Objective: The present study aimed to evaluate whether daylight PDT without curettage could be as effective as daylight PDT with curettage.

Methods: Twenty-five patients with multiple AKs were treated in two even-sized areas on the face and scalp. One area was treated with standard daylight PDT starting with curettage followed by incubation with methyl aminolevulinate (MAL) for 30 min before 2 h of daylight exposure. The other area was incubated with MAL for 1 h without prior curettage before 2 h of daylight exposure. The longer incubation time was used to obtain a sufficiently high protoporphyrin IX concentration in the non-curettaged area.

Results: There was no difference in cure rate 3 months after daylight PDT in areas pretreated with curettage (86%) compared to non-curettaged areas (84%) (P = 0.1). Neither was there any difference between reported pain during daylight exposure (P > 0.7) or clinically evaluated erythema the day after treatment (P = 1.0).

Conclusion: Daylight PDT without curettage but with 1 h of MAL incubation before daylight exposure was shown to be as effective in treatment of thin AKs on the face and scalp as standard daylight PDT with curettage. This modification of daylight PDT eases the task for the clinic and makes it more convenient for the patients as well, creating the possibility of performing daylight PDT as an entirely home-based treatment for AKs of the face and scalp without training the patients to perform pretreatment.