Daylight photodynamic therapy: the Southern California experience

Photodynamic therapy (PDT) is a safe and effective treatment for actinic keratoses (AKs) and photoactinic damage. Three elements are needed for PDT: a photosensitizer, oxygen, and a light source. Conventional PDT is performed with a variety of different laser and light sources including blue, yellow and red in addition to filtered intense pulsed lights (IPL). Daylight PDT, using ambient visible light has been reported as safe, time- and cost-efficient, and more comfortable than with other light sources. We report our experience with daylight PDT in 80 patients.

Eighty patients with multiple actinic keratoses related to chronic photodamage underwent one or two sessions with daylight PDT. Anatomic locations treated included face, chest, arms, and legs. Aminolevulinic acid (ALA, Levulan, Kerastick Dusa USA) was applied one hour prior to light exposure. Thick actinic keratoses were gently curetted prior to ALA application. A chemical sunscreen was applied thirty minutes into the incubation and subsequently patients sat outside in the shade for 2.5 hours. The following day, patients applied a chemical sunscreen and went into either shaded or direct sunlight for 15-30 extra minutes depending on sensitivity. Significant pain associated with this second day exposure was an indication to return indoors immediately. After the second exposure they were instructed to stay inside for the remainder of the 48 hour post treatment period.

All patients tolerated the procedure well. Patients denied any pain during the first two and half hour exposure. The second day exposure elicited a mild burning sensation that patients rated as a 2-3/10 though some patients elected to go outside protocol and 'tough it out' despite more significant discomfort. Patients and physicians noted significant reduction in photoactinic damage and actinic keratoses. Patients appreciated the convenience of the treatment. There were no significant adverse events, and no patients reported scarring.

In this case series, daylight PDT achieved obvious improvement in photodamage, specifically precancerous lesions, and in photoaging with a reduction in lentigenes and other signs of aging. Patients reported significantly less pain than with conventional PDT and enjoyed the convenience of treatment generally in their backyard. It was noted to be a safe procedure with no significant adverse events such as scarring. Additionally, the cost of the procedure was significantly reduced, with ALA and its application being the only expenses.