Comparative study of imiquimod 3.75% vs. photodynamic therapy for actinic keratosis of the scalp

Photodermatol Photoimmunol Photomed. 2021 Sep;37(5):404-409. doi: 10.1111/phpp.12671. Epub 2021 Feb 20.

Abstract

Background/purpose: To assess efficacy, tolerability, adverse effects, recurrence, and aesthetic results of imiquimod 3.75% vs. photodynamic therapy with 5-aminolaevulinic acid (MAL-PDT) for actinic keratosis (AK).

Methods: A small randomized, intraindividual right-left pilot study for AK treatment of multiple scalp lesions was performed. Patients were treated with imiquimod and subsequently MAL-PDT (on opposite sides of the scalp) 14 days apart. Study end points were evaluated with clinical and dermoscopic examinations at 1, 3, 6, and 12 months.

Results: Nine male bald patients were enrolled. Imiquimod achieved a slightly higher overall clearance rate than MAP-PDT (68.1% vs 56.5%). According to AK degree of severity, clearance rates were greater for degree I and III with imiquimod (68.8%, 64.5% and 75% with imiquimod vs. 48%, 69.8%, and 66.7% for MAL-PDT, respectively). At 12 months, a slightly higher total recurrence rate was noted for imiquimod compared with MAL-PDT (9.9% vs. 8.6%); new lesions were 2 degree I for imiquimod and 4 degree I for MAL-PDT. For both treatments, pain was moderate/strong (even if MAL-PDT seems to be less tolerable) adverse effects are common and transient; aesthetic results excellent.

Conclusion: Both imiquimod and MAL-PDT were effective in the reduction in the number of AK. In the long-term, both present a good effectiveness maintained over time with excellent aesthetic results. A combination or sequential therapy could optimize the management of the cancerization field.

Keywords: actinic keratosis; imiquimod 3.75%; photodynamic therapy.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aminolevulinic Acid / therapeutic use
  • Humans
  • Imiquimod
  • Keratosis, Actinic* / drug therapy
  • Male
  • Photochemotherapy*
  • Photosensitizing Agents / therapeutic use
  • Pilot Projects
  • Scalp
  • Treatment Outcome

Substances

  • Photosensitizing Agents
  • Aminolevulinic Acid
  • Imiquimod