Ablative Fractional Laser Enhances Artificial or Natural Daylight Photodynamic Therapy of Actinic Field Cancerization: A Randomized and Investigator-initiated Half-side Comparative Study - Original report

Sep 24, 2026

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Actinic keratoses are common precancerous lesions from chronic sun exposure, and daylight photodynamic therapy offers a non-surgical option, though it is approved mainly for grade I–II cases. This randomized single-blinded split-side study enrolled 60 patients with at least two head actinic keratoses to test whether ablative fractional laser pre-treatment improves daylight photodynamic therapy outcomes across all grades. Laser pre-treatment produced higher complete clearance, partial clearance, and lesion-specific clearance at 6 months, with similar results for artificial versus natural daylight and favorable tolerability and cosmesis.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages6

Reading Time15 min

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Significance

Study rationale and clinical background

Materials and Methods

Study design and participants

1/6 ORIGINAL REPORT Ablative Fractional Laser Enhances Artificial or Natural Daylight Photodynamic Therapy of Actinic Field Cancerization: A Randomized and Investigator-initiated Half-side Comparative Study Vivian LINDHOLM, Mari SALMIVUORI, Sonja HAHTOLA, Kerttu MÄKELÄ, Sari PITKÄNEN\# and Kirsi ISOHERRANEN\# Department of Dermatology, Allergology and Venereology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland \#These authors contributed equally. Artificial daylight photodynamic therapy is a nearpainless treatment for actinic keratoses, which can be performed indoors using a controlled light dose. Daylight photodynamic therapy is approved only for treatment of grade I–II actinic keratoses. The aim of this study was to evaluate whether fractional laser pre-treatment improves the outcomes of daylight photodynamic therapy for actinic keratoses of all grades. In addition, the study compared the outcomes of artificial and natural daylight photodynamic therapy. This randomized single-blinded split-side comparative study included 60 patients with ≥ 2 actinic keratoses of the head. Fractional laser pre-treatment was assigned randomly for actinic keratoses on 1 side of the head and, subsequently, the entire treatment area was treated with artificial or natural daylight photodynamic therapy. Fractional laser-mediated daylight photodynamic therapy achieved significantly higher complete clearance (50.0% vs 30.3%, p = 0.04), partial clearance (78.6% vs 50.0%, p < 0.01) and lesionspecific clearance (86.2% vs 70.2%, p < 0.01) than daylight photodynamic therapy alone at the 6-month follow-up. No significant differences were found in the outcomes of artificial vs natural daylight photodynamic therapy or grade I lesions vs grade II–III lesions. Thus, fractional laser pre-treatment appears to significantly increase the efficacy of artificial and natural daylight photodynamic therapy, and to be suitable for treatment of actinic keratoses of all grades. Key words: actinic keratosis; laser therapy; photochemotherapy. Accepted May 31, 2023; Published Aug 16, 2023 Acta Derm Venereol 2023; 103: adv6579 . DOI: 10. 2340/actadv.v103 .6579 Corr: Vivian Lindholm, Helsinki University Hospital, Skin and Allergy Hospital, Meilahdentie 2, 00250 Helsinki, Finland. E-mail: vivian.lindholm@ [helsinki.fi](helsinki.fi) Potodynption foarmactitherapnic fielyd PDTanceiaatis(t1-l)ine treatmThe efficeantcyand cosmetic outcomes of PDT are adequate; however, conventional PDT (cPDT) can cause extensive pain during treatment (1) . Daylight-PDT (dPDT) has been introduced as a near-painless treatment alternative to cPDT. It enables SIGNIFICANCE Actinic keratoses are common precancerous skin lesions caused by chronic sun exposure, which can evolve into squamous cell carcinoma. Treatment of actinic keratoses is non-surgical, and daylight photodynamic therapy is an option. This study of 60 patients with actinic keratoses investigated whether ablative fractional laser pretreatment increases the efficacy of daylight photodynamic therapy. At the 6-month follow-up visit, laser pre-treated lesions showed significantly higher complete clearance rates (50%) compared with daylight photodynamic therapy alone (30%) . Laser pre-treatment was effective in the treatment of actinic keratoses of all thicknesses (p>0.1) . In addition, the treatment was mostly well tolerated (35/37 patients) and the cosmetic result good (36/39 patients) . treatment of large areas and is as effective as cPDT for thin grade I–II actinic keratoses (AKs) (2) . However, for thicker AKs, the efficacy ofdPDT can decrease (3) . According to European guidelines, natural dPDT (ndPDT) can be used to treat grade I–II AKs at temperatures above 10°C from March to October in Finland, but not during rain (2) . In environments with variable and cold weather conditions, in particular, an option is artificial dPDT (adPDT) performed indoors, although this has not yet been exte

FAQs

What was the primary goal of the study?

To evaluate whether fractional laser pre-treatment improves the outcomes of daylight photodynamic therapy for actinic keratoses of all grades.

How was the fractional laser pre-treatment delivered in the trial?

Fractional laser pre-treatment was assigned randomly to actinic keratoses on one side of the head, followed by artificial or natural daylight photodynamic therapy to the entire treatment area.

Did artificial daylight photodynamic therapy perform differently from natural daylight photodynamic therapy?

No significant differences were found in outcomes between artificial and natural daylight photodynamic therapy at the 6-month follow-up.

Sep 24, 2026

Uploaded by Aditya