Daylight photodynamic therapy for prevention of new actinic keratosis and keratinocyte carcinomas in organ transplants. A cryotherapy-controlled randomized clinical trial.

Abstract

Organ transplant recipients (OTR) have a higher risk of actinic keratosis (AK) and keratinocyte carcinomas (KC). There are no clinical trials assessing the effectiveness of daylight photodynamic therapy (DPDT) to prevent new AK and KC in OTR. To determine whether repeated treatments of field cancerization with DPDT are effective in preventing new AK and KC in OTR. A randomized, intra-subject controlled, evaluator-blind, split-face and/or scalp trial, from April 2016 to October 2018. Participants were OTR older than 18years, 1-year posttransplant, with at least 5 AK on each hemi-face/hemi-scalp. One side received six field treatments with DPDT: two sessions 15days apart at baseline, two at 3months and two at 9months after baseline. Control side received lesion-directed treatment with cryotherapy (double freeze-thaw) at baseline, 3 and 9months. Total number of lesions (AK and KC) at 21months, number of new AK and KC at 3, 9, 15 and 21months and treatment preferences were analysed. Of 24 men included, 23 were analysed at 3months; and 21, at 9, 15 and 21months. Mean (SD) age was 69.8years (9.2). The total number of lesions at 21months was 4.7 (4.3) for DPDT and 5.8 (5.0) for control side; P=0.09. DPDT showed significantly lower means [SD] of new lesions compared to control side at 3months (4.2 [3.4] vs. 6.8 [4.8]; P<0.001), 9months (3.0 [3.3] vs. 4.3 [3.4]; P=0.04) and 15months (3.0 [4.6] vs. 4.8 [5.0]; P=0.02), and non-significant at 21months (3.7 [3.5] vs. 5.0 [4.5]; P=0.06). Most participants preferred DPDT. DPDT showed potential effectiveness in preventing new AK and KC in OTR by consecutive treatments of field cancerization. The preference for DPDT could facilitate adherence to the long-term treatment necessary in these patients.