Background: Transplant recipients have an increased propensity to develop multiple actinic keratoses, which demonstrate an increased transformation rate into invasive squamous cell carcinoma.
Objective: To evaluate the efficacy and tolerability of topical photodynamic therapy with the new highly tumour-selective photosensitizer methyl aminolaevulinate vs. placebo in the treatment of actinic keratoses in transplant recipients.
Methods: Seventeen transplant recipients with a total number of 129 mild to moderate actinic keratoses were enrolled in a prospective, randomized, double-blind, placebo-controlled study. Two lesional areas within a patient were randomized for two consecutive treatments of topical photodynamic therapy 1 week apart using either methyl aminolaevulinate or placebo cream. Sites were illuminated with 75 J cm(-2) of visible light delivered at 80 mW cm(-2) by a noncoherent light source. Complete resolution and reduction in the number or size of actinic keratoses within the lesional area relative to the initial findings were evaluated at weeks 4, 8 and 16 after treatment.
Results: The lesional areas treated with methyl aminolaevulinate were clinically cleared in 13 of 17 patients at 16 weeks. A partial response was recorded in a further three. No reduction in the size or number of actinic keratoses was observed in one area treated with methyl aminolaevulinate and in all placebo-treated areas. Adverse events, such as erythema, oedema and crust formation, were mild to moderate, and treatment was well tolerated by all patients.
Conclusion: Photodynamic therapy using methyl aminolaevulinate is a safe and effective treatment for actinic keratoses in transplant recipients. It may also reduce the risk of transformation of actinic keratoses to invasive, potentially fatal, squamous cell carcinoma.