Continuous activation of PpIX by daylight is as effective as and less painful than conventional photodynamic therapy for actinic keratoses; a randomized, controlled, single-blinded study.
BACKGROUND
Photodynamic therapy (PDT) is a highly effective treatment for actinic keratoses (AK); however, it is time consuming and often painful for the patient. Daylight-PDT would make the treatment independent of the clinic and less painful due to the continuous activation of small amounts of porphyrins during its formation.


OBJECTIVE
The objective of this randomized controlled study was to compare response rates and adverse effects after methyl aminolevulinate (MAL)-PDT using conventional red light-emitting diode (LED) light vs. daylight.


METHODS
Twenty-nine patients with AK of the face and scalp were treated with MAL-PDT in two symmetrical areas. One area was illuminated by red LED light (37 J cm(-2)) after 3-h incubation with MAL under occlusive dressing. The other area was treated with daylight for 2.5 h after the MAL cream had been under occlusion for half an hour.


RESULTS
We found no significant difference in the treatment effect between the two treatments (P = 0.13), with a reduction of AK lesions of 79% in the daylight area compared with 71% in the LED area. Treatment response in the daylight area did not depend on the intensity of the daylight. Illumination with LED was more painful than daylight (P < 0.0001). Erythema and crusting occurred after both treatments and were similar in the two areas.


CONCLUSIONS
PDT of AK by continuous activation of porphyrins by daylight proved to be as effective as conventional PDT. PDT using daylight activation will make the treatment of these extremely common premalignant tumours more time and cost effective, and more convenient for the patient.
Wiegell
S R
SR
Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, Copenhagen NV, Denmark. srw01@bbh.regionh.dk
Haedersdal
M
M
Philipsen
P A
PA
Eriksen
P
P
Enk
C D
CD
Wulf
H C
HC
D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005148:Facial Dermatoses / Q000188:drug therapy; D005260:Female; D006370:Heliotherapy / Q000379:methods*; D006801:Humans; D007642:Keratosis / Q000150:complications / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D010778:Photochemotherapy / Q000009:adverse effects*; D017319:Photosensitizing Agents / Q000009:adverse effects / Q000627:therapeutic use*; D011524:Protoporphyrins / Q000009:adverse effects / Q000627:therapeutic use*; D012536:Scalp Dermatoses / Q000188:drug therapy; D016037:Single-Blind Method; D016896:Treatment Outcome
D017319:Photosensitizing Agents; D011524:Protoporphyrins; C475457:methyl 5-aminolevulinate; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX