Daylight photodynamic therapy of actinic keratosis without curettage is as effective as with curettage: a randomized clinical trial

Abstract

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.

How Much Protoporphyrin IX Must Be Activated to Obtain Full Efficacy of Methyl Aminolevulinate Photodynamic Therapy? Implication for Treatment Modifications

“…This is also the case when performing continuous activation with daylight PDT, even though only 85% of PpIX is activated compared to the amount activated in classic PDT. The full effect on AK of the face and scalp is also observed after activation of 57-52 PpIX units, as in pulse PDT and PDT without curettage [8,9]. Thus, continuous activation of 50 PpIX units specifically located intracellularly may be close to the minimum level of PpIX activation needed to obtain the full effect of the PDT treatment, but it is possible that the necessary PpIX activation may be even lower.…”

“…Daylight PDT without curettage [9] involves MAL application to the face and scalp without pre-treatment. The continuous daylight illumination begins after 1 h and ends 3 h after MAL application.…”

Measuring Daylight: A Review of Dosimetry in Daylight Photodynamic Therapy

“…[17] RCT Illuminance N/A P20 2 48773 (lx) 10600-86357 (lx) O'Gorman [18] RCT Irradiance, illuminance and spectral irradiance. N/A P20 2 21.38 3.2-43 Nissen [19] RCT Illuminance N/A P20 2 36477 (lx) 1322-94234 (lx) Räsänen [20] RCT Irradiance N/A P20 2 12.89 5.96-17.93 Heerfordt [21] RCT Illuminance N/A N/A 2 38640 (lx) 7200-85200 (lx) Wiegell [22] Dose measurement Wristwatch (PpIX-weighted) […”

“…A study by Heerfordt and Wulf in 2019 investigating curettage procedures before DPDT used a similar rationale for dosimetry [21]. Illuminance was measured on a luxmeter (Model E2; Hagner, Solna, Sweden) prior to and at the end of the two-hour treatment.…”

Management Pearls on the Treatment of Actinic Keratoses and Field Cancerization

“…The photosensitizer (MAL or ALA) is applied for 30 min after curettage on the face or scalp, and the patient is instructed to expose the face or scalp to daylight for 2 h. The incidence of complete response has been reported to be similar between daylight PDT and conventional PDT, but with lower risk of adverse events, and daylight PTD is better tolerated [ 29 ]. In order to avoid the discomfort and bleeding caused by curettage, the photosensitizer can be applied for 1 h before daylight exposure [ 30 ]. Cold analgesia.…”