Field cancerization treatment: Adjustments to an ALA red light photodynamic therapy protocol to improve pain tolerance

Author(s)

Salvio, Ana Gabriela ^[1] ; Stringasci, Mirian D. ^[2] ; Requena, Michelle B. ^[2] ; Oliveira, Elisangela Ramos de ^[1] ; Medeiro, Maira Monique da Costa ^[1] ; Bagnato, Vanderlei Salvador ^{[3, 2]}

Affiliation

^[1] Amaral Carvalho Hosp, Skin Dept, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Sao Carlos Inst Phys, Sao Carlos, SP - Brazil

^[3] Texas A&M Univ, College Stn, TX - USA

• Document type: Journal article
• Source: Photodiagnosis and Photodynamic Therapy; v. 35, SEP 2021.
• Web of Science Citations: 0

Abstract

Background: Field cancerization (FC) is described as an area with multiple actinic keratosis (AK) in an actinic damaged skin that requires treatment. Photodynamic therapy (PDT) is a treatment option, however, long drug light intervals (DLI) and pain during the illumination remain a challenge Objective: Pain and the efficacy of changes in DLI and illumination during PDT treatment for FC were evaluated Methods: Thirty patients with widespread AK of upper limbs were selected. A 20% aminolevulinic acid (ALA) cream was applied on both forearms and hands after a light curettage. Three groups were evaluated: G1 (3 h of DLI); G2 (1.5 h of DLI); and, G3 (1.5 h of DLI with two-minutes pauses every 10 min during illumination). The limbs were treated with a LED prototype at 630 nm (36 J/cm(2) of fluence in 40 min of irradiation). The pain score during illumination was evaluated with a numeric scale (from 0 to 10) and pain was defined as low (0-3), moderate (4-6), and severe (7-10). The AK counting was clinically performed before and 30 days after PDT. Significance between groups was tested using ANOVA single factor. Results: A mean reduction in AK number of 56% in G1, 55% in G2, and 66% in G3 were observed, with no statistical significance. The comparison pain among the groups showed best results for G3 (p < 0,05). Conclusion: Using paused illumination and 1.5 h of DLI was possible to improve tolerance maintaining the clearance in red light ALA - PDT treatment. (AU)

• FAPESP's process: 09/54035-4 - Facility for advanced studies of biosystems and nanostructured materials
• Grantee: Igor Polikarpov
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 13/07276-1 - CEPOF - Optics and Photonic Research Center
• Grantee: Vanderlei Salvador Bagnato
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 14/50857-8 - National Institute in Basic Optics and Applied to Life Sciences
• Grantee: Vanderlei Salvador Bagnato
• Support Opportunities: Research Projects - Thematic Grants