1. Background and Objectives Port-wine stain (PWS) is a congenital capillary malformation located in the upper dermis. Hematoporphyrin monomethyl ether (HMME)-mediated photodynamic therapy (PDT) has been established as a primary and effective treatment for PWS in China. However, treatment parameters, particularly irradiance and irradiation duration, vary widely in clinical practice based on physician experience, with a lack of evidence from controlled trials to guide optimization. The efficacy of PDT relies on a type II photochemical reaction, which is oxygen-dependent. High irradiance may lead to rapid oxygen depletion in the treatment area, potentially limiting therapeutic outcomes. This prospective, randomized controlled trial aims to compare the efficacy and safety of a low-irradiance, prolonged-duration protocol versus a high-irradiance, shorter-duration protocol in HMME-PDT for PWS, while maintaining an identical total light dose.
2. Study Design
This was a single-center, randomized controlled, single-blind trial. The study protocol was approved by the Ethics Committee of The Second Affiliated Hospital of Xi'an Jiaotong University (Approval No. 2024219). A total of 33 pediatric patients (aged 3-12 years) with facial or neck PWS were enrolled and randomly assigned to one of two groups:
Low-Power Group (n=15): Received irradiation at 75 mW/cm² for 19 minutes per spot.
High-Power Group (n=18): Received irradiation at 84 mW/cm² for 17 minutes per spot.
Both groups received a single session of HMME-PDT with the same total light dose. All patients received an intravenous infusion of Hemoporfin at a dose of 5.0 mg/kg, followed by irradiation with a 532-nm LED green light.
3. Primary evaluation indicators
The primary efficacy endpoint was lesion clearance assessed at the 3-month follow-up using three independent methods:
Blinded Quartile Grading: Performed by two independent dermatologists based on high-resolution photographs.
Quantitative Lesion Area Reduction: The percentage reduction in the PWS area was calculated from VISIA complexion analysis system "redness" images using ImageJ software.
Erythema Index (EI) Analysis: The relative change in the EI (ΔEI%) between the lesion and normal skin was quantified.