Indoor Daylight Photodynamic Therapy is an Effective, First-line Treatment for AK, But Its Feasibility is Limited by the Time Required for the Illumination (2 Hours). Our Objective Was to Evaluate the Efficacy of Idl-PDT With an Illumination Time of 1 Hour Versus 2 Hours in the Treatment of Scalp AK

Indoor Daylight Photodynamic Therapy for Actinic Keratosis of the Scalp: Intra-patient Comparison Study of 1 Hour Versus 2 Hours Exposure Time

Several treatments are available for actinic keratosis (AK), many of which are hampered by local inflammation, pain, long duration, and slow healing. Indoor daylight photodynamic therapy (idl-PDT) is an effective, well-tolerated, first-line treatment for both AK and field cancerization, but the feasibility of this treatment is limited by the long time required for the illumination (2 hours). Objective of this study was to evaluate the efficacy of idl-PDT with an illumination time of 1 hour versus 2 hours in the treatment of scalp AK. Adult patients (age >50 years) with multiple AK located on the scalp (at least 5 Olsen grade I or II AK in two symmetrical areas) and diagnosed according to the typical clinical appearance were enrolled at two Dermatology Units in Italy. Exclusion criteria were the followings: previous treatment for AK within 6 months; status of congenital, infectious, or iatrogenic immunodepression; known cutaneous photosensitivity; known hypersensitivity to any ingredient of Metvix® 135 mg/g cream (Galderma SA, Lausanne, Switzerland). AK lesions on the scalp were mapped photographically with the support of a transparent sheet and graded according to Olsen grading scale. Two contralateral and symmetric areas of the scalp containing at least 5 AK were identified. Randomization of the two target areas for the two illumination durations (1 hour vs 2 hours) was performed with a 1:1 allocation ratio with a computer-generated list using permuted random blocks of six to ensure allocation concealment. At baseline, the following data were recorded: age, sex, phototype, Olsen grade and number of AK per side, any previous therapies on the treated area, any previous surgical excision of malignant skin neoplasms on the treated area, and comorbidities. The skin area to be treated was prepared with a sterile gauze pad soaked in saline solution to remove scales and crusts and then a 1 mm thick layer of cream containing 160mg/g of MAL (Metvix®) was applied. After 30 minutes of application, according to clinical practice and approved protocol, exposure to the white polychromatic LED lamp (Dermaris®, Surgiris, Croix, France, 400-700nm, fixed distance 30 cm, irradiance 72.6 W/m2 156 ) was performed, for a duration of 1 hour on one half and 2 hours on the other half, according to randomization. The emission spectrum of the light source was measured with a SR 9910 spectroradiometer (Macam Photometrics Ltd, Livingston, UK). The light doses were 26.1 J/cm2 for 1 hour illumination and 52.3 J/cm2 for 2 hours illumination, and the effective light doses for PpIX photoactivation were 0.69 Jeff/cm2 160 for 1 hour illumination and 1.39 Jeff/cm2 for 2 hours illumination. The effective light dose was calculated with the normalized PpIX absorption spectrum, the spectral irradiance of the lamps and treatment duration. Patients were evaluated 3 months and 6 months after the idl-PDT session to assess the efficacy of the two illumination times. A clinical photograph of the treated area was taken after 1 hour, 24 hours, and at each of the two follow-up visits. The primary endpoint of the study was the lesion response rate at 3 months. The analysis was performed on the total number of AK and after categorization of AK according to Olsen clinical grade. The secondary endpoints were lesion response rate at 6 months, tolerability and physicians' and patients' satisfaction. Tolerability was assessed as follows: subject's assessment of maximal pain perceived according to treated side immediately after the end of the treatment on a 0-10 numeric rating scale (NRS), from 0 (no pain) to 10 (extreme pain); local skin reactions (LSRs) assessed 1 hour and 24 hours after the treatment, including erythema, scaling, crusting, edema, blistering/pustulation and erosion/ulceration, each classified according to a 0-4 scale of severity (total LSR score range: 0-24). At the 3-months follow up visit, physicians rated their level of satisfaction on a 4-point scale with respect to treatment efficacy (very effective, effective, poorly effective, ineffective) and cosmetic outcome (excellent, good, poor or worse) for each treated area. In addition, patients were administered a questionnaire to globally assess convenience of the treatment (very convenient, convenient, poorly convenient, inconvenient) and overall level of satisfaction (very satisfied, satisfied, poorly satisfied, not satisfied at all) on a 4-point scale. The patient's willingness to undergo any further treatment with idl-PDT was recorded.

Study Overview

• Status: Completed
• Conditions: Actinic Keratosis (AK)
• Intervention / Treatment: Other: We conducted an intra-patient, comparative study of idl-PDT with two illumination durations, 1 hour vs. 2 hours, using methyl aminolevulinate and a white LED light for the treatment of scalp AK.

• Study Type: Interventional
• Enrollment (Actual): 55
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • L’Aquila, Italy, 67100
    • Ospedale San Salvatore

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adult patients (age >50 years) with multiple AK located on the scalp (at least 5 Olsen grade I or II AK in two symmetrical areas) and diagnosed according to their typical clinical dermoscopic appearance
• Subject must be able to understand and be willing to adhere to all protocol requirements and voluntarily sign and date an informed consent

Exclusion Criteria:

• previous treatment for AK within 6 months;
• status of congenital, infectious, or iatrogenic immunodepression;
• known cutaneous photosensitivity;
• known hypersensitivity to any ingredient of Metvix® 160 135 mg/g cream (Galderma SA, Lausanne, Switzerland).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: AK patients

Other: We conducted an intra-patient, comparative study of idl-PDT with two illumination durations, 1 hour vs. 2 hours, using methyl aminolevulinate and a white LED light for the treatment of scalp AK.; The skin area to be treated was prepared with a sterile gauze pad soaked in saline solution to remove scales and crusts and then a 1 mm thick layer of cream containing 160mg/g of MAL (Metvix®) was applied. After 30 minutes of application, according to clinical practice and approved protocol, exposure to the white polychromatic LED lamp (Dermaris®, Surgiris, Croix, France, 400-700nm, fixed distance 30 cm, irradiance 72.6 W/m2) was performed, for a duration of 1 hour on one half and 2 hours on the other half, according to randomization. The emission spectrum of the light source was measured with a SR 9910 spectroradiometer (Macam Photometrics Ltd, Livingston, UK). The light doses were 26.1 J/cm2 for 1 hour illumination and 52.3 J/cm2 159 for 2 hours illumination, and the effective light doses for PpIX photoactivation were 0.69 Jeff/cm2 for 1 hour illumination and 1.39 Jeff/cm2 for 2 hours illumination. The effective light dose was calculated with the normalized PpIX absorption spectrum.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The primary outcome of the study was the clinical clearance rate of actinic keratosis 3 months after the idl-PDT treatment, both overall and stratified by Olsen clinical grade	Treatment efficacy was measured by calculating the rate of complete clinical remission of actinic keratosis per 100 lesions-patient (defined by the number of completely responding actinic keratosis divided by the number of lesions treated at baseline) within each treated half. Comparison of treatment efficacy in the two halves (1h-half vs 2h-half) was analyzed by paired T-test. Statistical analysis was conducted with SPSS software (IBM) version 25.0 (SPSS Inc., Chicago, IL, USA). Differences were considered significant for p-values < 0.05.	3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain perceived during the treatment, assessed with Numeric Pain Rating Scale (0-10)	The maximum pain perceived by the patients on each treated half was assessed using the Numerical Rating Scale (NRS) for pain, ranging from 0 (no pain) to 10 (extreme pain).	Immediately after the end of the treatment
Cutaneous adverse events assessed with Local Skin Reactions (LSR) scale	Local skin reactions (LSRs) were assessed using LSR rating scale, considering six items (erythema, scaling, crusting, edema, blistering/pustulation and erosion/ulceration), each classified according to a 0-4 scale of severity (total LSR score range: 0-24).	1 hour and 24 hours after the treatment
Physicians' satisfaction to treatment efficacy	Physicians rated their level of satisfaction on a 4-point scale with respect to treatment efficacy (very effective, effective, poorly effective, ineffective) for each treated area.	3 months after the treatment
Physicians' satisfaction with cosmetic outcome	Physicians rated their level of satisfaction on a 4-point scale with respect to cosmetic outcome (excellent, good, poor or worse) for each treated area.	3 months after the treatment
Patients' global opinion on the treatment	Patients were administered a questionnaire to globally assess their global opinion on the convenience of the treatment on a 4-point scale (very convenient, convenient, poorly convenient, inconvenient).	3 months after the treatment
Patients' overall level of satisfaction	Patients were administered a questionnaire to globally assess their overall level of satisfaction on the treatment on a 4-point scale (very satisfied, satisfied, poorly satisfied, not satisfied at all).	3 months after the treatment

Collaborators and Investigators

• Sponsor: San Salvatore Hospital of L'Aquila

Study record dates

Study Major Dates

• Study Start (Actual): January 2, 2025
• Primary Completion (Actual): July 1, 2025
• Study Completion (Actual): July 15, 2025

Study Registration Dates

• First Submitted: November 17, 2025
• First Submitted That Met QC Criteria: December 4, 2025
• First Posted (Actual): December 18, 2025

Study Record Updates

• Last Update Posted (Actual): December 18, 2025
• Last Update Submitted That Met QC Criteria: December 4, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms; Skin Diseases; Precancerous Conditions; Keratosis; Skin and Connective Tissue Diseases; Keratosis, Actinic
• Other Study ID Numbers: C.Et.R.A. 47/2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No