Sandpaper curettage: A simple method to improve PDT outcomes for actinic keratosis

• Published in: Photodiagnosis and photodynamic therapy 2022-12, Vol.40, p.103050-103050, Article 103050
• Main Authors: Heusinkveld, Lauren E., Bullock, Taylor A., Negrey, Jeffrey, Warren, Christine B., Maytin, Edward V.
• Format: Article
• Language: English
• Subjects: Actinic keratosis; Aged; Aminolevulinic Acid - therapeutic use; Clinical Studies as Topic; Curettage; Female; Humans; Keratosis, Actinic - drug therapy; Male; Photochemotherapy - methods; Photodynamic therapy; Photosensitizing Agents - therapeutic use; Retrospective Studies; Sandpaper curettage; Treatment Outcome
• ISSN: 1572-1000; 1873-1597
• DOI: 10.1016/j.pdpdt.2022.103050

•Photodynamic therapy (PDT), using topical ALA followed immediately by blue light, is a painless treatment for actinic keratoses (AK); its efficacy could be improved.•Sandpaper abrasion is a simple yet underexplored PDT pretreatment.•AK clearance outcomes were compared for two groups of patients (Group 1, PDT alone; Group 2, sandpaper curettage then PDT).•Group 2 lesion clearance was significantly improved (by 55%) on the scalp, with no increase in side effects.•Sandpaper curettage is an easy, safe, and inexpensive way to improve PDT for AK. Photodynamic therapy (PDT) is a non-scarring, repeatable, and safe treatment for actinic keratosis (AK), but improvements in efficacy are still needed. Devices such as steel blades, needle rollers, and lasers are currently used to remove hypertrophic stratum corneum on AKs to improve PDT outcomes. However, curettage with fine sandpaper could be a gentler, effective alternative. A retrospective study was designed to compare PDT with or without sandpaper curettage. Patients were selected from a database registry of patients with face and scalp AKs (ClinicalTrials.gov NCT03319251). Patients in Group 1 underwent PDT alone (20% ALA, 15 min; blue light 417 nm, 30 min). Patients in Group 2 were pretreated with gentle sandpaper curettage prior to ALA and illumination. The two groups were compared using multivariate matching, normalizing for age, sex, initial AK counts, and time to follow-up. Sixty-six patients were selected for matching analysis (n=38, PDT only; n=28, PDT+curettage). Demographics between the groups were similar (mean ± SD), including age (71.0 ± 8.3 vs. 71.0 ± 8.0 years), baseline AK count (53 ± 39 vs. 44± 32), and time to post-PDT follow-up (111 ± 28 vs. 113 ± 32 days). At follow-up, patients who received curettage showed an overall 55% improvement in scalp AK clearance compared to patients who did not receive curettage, adjusting for sex, age, time to follow-up, and baseline AK count (p = 0.0322, multivariable linear regression). Sandpaper curettage before PDT treatment is an easy and inexpensive method to significantly improve AK clearance rates.