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Video. Video Illustration Depicting the Microneedle Roller and Application Technique

Videography by Buno Photography and Video, Sacramento, California.

Original Investigation
July 2017

Effect of Expedited Microneedle-Assisted Photodynamic Therapy for Field Treatment of Actinic Keratoses: A Randomized Clinical Trial

Author Affiliations
  • 1Department of Dermatology, University of California–Davis, Sacramento
  • 2School of Medicine, University of California–Davis, Sacramento
JAMA Dermatol. 2017;153(7):637-643. doi:10.1001/jamadermatol.2017.0849
Key Points

Question  Can microneedle pretreatment expedite photodynamic therapy (PDT) for field treatment of actinic keratoses (AKs)?

Findings  In this randomized clinical trial, pretreatment with microneedles before a 20-minute incubation of aminolevulinic acid (ALA) resulted in AK clearance of 76%, which is similar in efficacy to conventional PDT with 1-hour ALA incubation time. In addition to expediting the protocol, microneedle pretreatment resulted in virtually painless PDT.

Meaning  The findings are promising for shortening treatment time and achieving greater patient satisfaction for PDT without compromising efficacy.


Importance  Photodynamic therapy (PDT) is an effective and cosmetically favorable treatment modality for actinic keratoses (AKs). However, prolonged incubation times and pain associated with treatment are burdensome to the patient and a hindrance to widespread use of PDT as standard field therapy for AK.

Objective  To evaluate efficacy and pain associated with microneedle expedited PDT.

Design, Setting, and Participants  The Microneedle Photodynamic Therapy II (MNPDT-II) study was a randomized, single-blinded, split-face controlled, 2-arm clinical trial. Thirty-three participants with AK on the face were recruited in a university dermatology outpatient clinic from 2015 to 2016, and 32 participants completed the study.

Interventions  Participants were randomized into 2 incubations arms, either 10-minute or 20-minute aminolevulinic acid (ALA) incubation times, after pretreatment with a microneedle roller (200 um) vs a sham roller. They were blinded to the laterality of microneedle and sham roller assignments. After incubation, they were exposed to blue light (Blu-U, Dusa Pharmaceuticals) for 1000 seconds for a total fluence of 10 J/cm2.

Main Outcomes and Measures  The primary outcome was to quantitatively measure AK resolution, and the secondary outcome was to assess pain associated with microneedle pretreatment.

Results  Thirty-three individuals were recruited and randomized to either the 20-minute or the 10-minute incubation arm. Thirty-two participants completed the study with a mean follow-up time of 34.5 days in the 20-minute group, and 30.2 days in the 10-minute group. For the 20-minute incubation arm, average AK clearance was 76% vs 58% on the sham side (P < .01), including 3 patients with complete clearance, although not statistically significant (P = .25). Pain assessment on the visual analog scale (VAS) during blue light illumination was not significantly different between the microneedle and sham sides (0.7 and 0.4; P = .28), respectively. For the 10-minute incubation arm AK clearance for the microneedle pretreated side was 43% compared with 38% on the sham side (P = .66). Pain during the blue light exposure was not significantly different between the microneedle and sham sides, 4.5 mm and 3.4 mm (P = .21), respectively.

Conclusions and Relevance  Photodynamic therapy with microneedle pretreatment at a 20-minute ALA incubation time significantly improved AK clearance with efficacy similar to that of a conventional 1-hour ALA incubation time. The additional advantage to expedited treatment was that the procedure was virtually painless. However, expedited exposure of a 10-minute ALA incubation time did not reach significantly different AK clearance from the sham control.

Trial Registration  clinicaltrials.gov Identifier: NCT02594644