COPENHAGEN – Twice-yearly prophylactic photodynamic therapy for primary prevention of actinic keratoses and squamous cell carcinomas is a novel and effective strategy that addresses the problem of accelerated photocarcinogenesis in organ transplant recipients, according to an interim analysis of a multinational, randomized, controlled trial.
“The overall aim is to prevent squamous cell carcinoma development. Photodynamic therapy is well established for secondary prevention of further AKs, and these very early data show that it can also be used for primary prevention in very high-risk patients,” Dr. Katrine Togsverd-Bo said at the annual congress of the European Academy of Dermatology and Venereology.
Accelerated carcinogenesis on sun-exposed skin is a major concern in organ transplant recipients (OTRs). They experience early onset of multiple AKs, with field cancerization and up to a 100-fold increased risk of squamous cell carcinomas (SCCs). Moreover, their SCCs are at substantially greater risk of metastasis than SCCs occurring in the general population, noted Dr. Togsverd-Bo of Bispebjerg Hospital and the University of Copenhagen.
She presented an interim analysis of an ongoing 5-year prospective randomized trial in 50 renal transplant recipients at academic dermatology centers in Copenhagen, Oslo, and Gothenburg, Sweden. All participants had clinically normal-appearing skin at baseline, with no history of AKs or SCCs. They are undergoing twice-yearly, split-side photodynamic therapy (PDT) on the face, forearm, and hand, with the opposite side serving as the untreated control.
To date, 25 patients have completed 3 years of the study. At 3 years of prospective follow-up by blinded evaluators, 50% of patients had AKs on their untreated side, compared with 26% on the prophylactic PDT side. The collective number of AKs on untreated skin was 43, compared with just 8 AKs on PDT-treated skin. Seven patients had AKs only on their untreated side, six had AKs on both sides, and none had any AKs only on their PDT-treated side.
The twice-yearly prophylactic PDT regimen consists of a 3-hour application of 20% methyl aminolevulinate as a photosensitizer followed by applications of a conventional LED light at 37 J/cm2.
Dr. Togsverd-Bo reported having no financial conflicts regarding her study.