Treating Field Cancerization by Ablative Fractional Laser and Indoor Daylight: Assessment of Efficacy and Tolerability

April 2020 | Volume 19 | Issue 4 | Case Reports | 425 | Copyright © April 2020


Published online March 20, 2020

Uwe Paasch , Tamer Said

aKlinik und Poliklinik für Dermatologie, Venerologie und Allergologie, Universitätsklinikum Leipzig AöR und Medizinische Fakultät der Universität Leipzig, Tiliaderm Institut für dermatologische Lasertherapie bDepartment of Dermatology, Venereology and Andrology. Faculty of Medicine, Alexandria University, Egypt

Abstract
Objective: To assess if ablative fractional laser combined with indoor daylight photodynamic therapy are effective and safe for the treatment of skin field cancerization associated with actinic keratosis (AK).
Methods: A total of 46 patients with field cancerized skin and AK were treated by a single session of laser assisted drug delivery (LAAD) and indoor daylight photodynamic therapy (IDL-PDT). LAAD was applied using a CO2 ablative fractional laser (AFXL) and aminolevulonic acid. Thereafter, IDL-PDT was administered using a novel device that mimics the sun radiation with a total dose of 48 J/cm².
Results: All patients showed remission following subsequent to the study protocol (complete: 71.7%, partial: 28.3%). Pain scores using a visual analog scare immediately following treatments were 9.0 ± 2.0.
Conclusions: AFXL-LAAD combined with IDL-PDT is extremely effective for the treatment of skin field cancerization associated with AK. Nevertheless, the high pain scores associated with this combined approach may prove to be a limiting factor. Thus, further protocol modifications in larger scale studies are still warranted.

J Drugs Dermatol. 2020;19(3): doi:10.36849/JDD.2020.4589

INTRODUCTION

Field cancerization, which is commonly associated with actinic keratosis (AK), depicts the accumulation of genetic alterations in cells adjacent to a primary tumor leading to premalignant transformation and potentially new primary tumors.1 Photodynamic therapy (PDT) has been established as one of the most widely used and effective treatment options for AK. Most importantly, its ability to treat large and multiple lesions makes it ideal for managing field cancerization.2 Despite being generally well tolerated, PDT-induced pain remains a significantly limiting factor.3 Replacing the artificial light emitting devices with daylight PDT (DL-PDT) appears to be somewhat effective in reducing PDT-induced pain.4 However since DL-PDT is dependent on the naturally occurring sun light, its outcomes are readily influenced by several factors such as seasonal variations, ambient temperature fluctuations, and the emission of UVB.5 These limitations could be hypothetically avoided by developing a standardized indoor light (IDL) source that mimics the effective sun radiation spectrum. In support, several currently available IDL devices have been used in the context of PDT.6 Another modification to the classical PDT protocol entails the integration of laser assisted drug delivery (LAAD). The combination of LAAD with PDT has been reported to result in increased efficiency and decreased photosensitizer incubation time.7,8 The objective of this pilot study was to evaluate the clinical efficacy and tolerability of a novel IDL device for PDT in combination with LAAD in patients with AK field cancerized skin.

METHODS

Forty-six patients diagnosed with field cancerized skin in association with AK were included in this retrospective study. Field cancerization was defined by the presence of more than 5 AK lesions. All clinical evaluations were performed by a single board-certified dermatologist. All patients provided informed written consent prior to participating in the study. Initially, AK lesions were prepared by removing any existing crusts using 25% trichloroacetic acid chemical peels over the course of 1 – 3 sessions. All patients received a single treatment cycle that consisted of LAAD and IDL-PDT. On the day of the treatment, LAAD was performed by targeting the treatment areas with an ablative fractional laser (AFXL, Pixel CO2, 10,600 nm, Alma Lasers Ltd, Caesarea, Israel) adjusted to the following settings in paintbrush mode: coverage 6%, spot size 120 μm, pulse duration 0.5