Background: Photodynamic therapy (PDT) has been reported as a treatment for cutaneous squamous cell carcinoma in situ (SCCis), but only limited data are available on the effectiveness of PDT with aminolevulinic acid (ALA-PDT).
Objective: To review the outcomes of SCCis treated with ALA-PDT and examine factors associated with response.
Methods: A retrospective review identified 58 patients with 68 primary SCCis lesions treated with ALA-PDT and blue light illumination. Patient demographics, lesion features, treatment details, clinical response, and subsequent recurrence were extracted from medical record reviews.
Results: On completion of PDT the initial complete response rate was 77.9% and was not associated with the number of PDT treatments. On multivariate analysis factors associated with response were location on the face, tumor diameter <2 cm, and longer ALA incubation time. Lesions treated with a maximum incubation time of <3 hours had a 53.3% response compared with 84.9% for longer incubation. Subsequent recurrence of SCCis was noted in 7 of 53 cases (13.2%) at a median time of 11.7 months.
Limitations: This was a retrospective study performed at a single institution without systematic follow-up.
Conclusions: ALA-PDT may be an effective treatment for selected cases of SCCis. Effectiveness is impacted by anatomic location, tumor diameter, and ALA incubation time.
Keywords: Bowen disease; aminolevulinic acid; humans; photodynamic therapy; retrospective studies; skin neoplasms; squamous cell carcinoma in situ; treatment outcome.
Copyright © 2019 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.