A randomized controlled clinical trial of topical photodynamic therapy with methyl aminolaevulinate in the treatment of actinic keratoses in transplant recipients

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Abstract
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.