Photodynamic Therapy Using Topical Aminolevulinic Acid in Treating Patients With Actinic Keratosis

OBJECTIVES:

Primary

• To determine, using fluorescence measurements, the protoporphyrin IX (PpIX) accumulation in thin actinic keratoses (AK) and actinically damaged skin on the face, scalp, and upper torso (stratum 1) and the PpIX accumulation in thick AK and actinically damaged skin on the arms and legs (stratum 2) as a function of skin preparation, aminolevulinic acid (ALA) application time, and body site.
• To determine the extent that the PpIX is photobleached by the treatment light.

Secondary

• To assess the effects of different treatment conditions on acute reactions of AK and sun damaged skin to ALA-photodynamic therapy (PDT) occurring 24-48 hours after PDT.
• To assess the effects of different treatment conditions on the efficacy of ALA-PDT.
• To examine the histological response to ALA-PDT.
• To determine, using fluorescence measurements, the PpIX accumulation in incidental thick AK that may occur in stratum 1, and the PpIX accumulation in incidental thin AK that may occur in stratum 2 as a function of skin preparation, ALA application time and body site.
• To determine the extent that the PpIX in these incidental lesions is photobleached by treatment light.

OUTLINE: The randomization is a two-step restricted block process for application time and skin preparation, followed by randomization for light dose (1 vs 2 pulses) within the anatomic site. Within each stratum (stratum 1 or 2), lesions in each separate anatomic area (face and neck, scalp, upper torso; arms, legs) are randomized to receive 1 of 3 pretreatment skin preparation before receiving topical aminolevulinic acid (ALA): pretreatment with acetone, gentle abrading, or no pretreatment. Patients are randomized to receive ALA at different times before the photodynamic therapy (PDT).

• Arm I: Patients receive topical ALA 2 hours before PDT.
• Arm II: Patients receive topical ALA 4 hours before PDT.
• Arm III: Patients receive topical ALA 24 hours before PDT. Each anatomic area is divided into subunits (e.g., right and left arm, right and left side of the face). The subunits are randomized to receive 1 or 2 pulses of the laser treatment.
• Arm IV: 1 Vbeam laser pulse (photodynamic therapy) is applied to the subunit.
• Arm V: 2 Vbeam laser pulses (photodynamic therapy) are applied to the subunit. Patients may receive up to 3 treatments (including pretreatment, ALA, and PDT) at least 1 month apart. Patients with progressive lesions or lesions that have not responded after 3 treatments may receive diagnostic biopsy to check for invasive squamous cell carcinoma and referred to treatment off study.

Patients undergo biopsies at baseline, before and after ALA application prior to light treatment, and up to 24 hours after light treatment to analyze cytokines and genes specific to actinic keratoses.