HHS Public Access Author manuscript Author Manuscript
Photodiagnosis Photodyn Ther. Author manuscript; available in PMC 2016 December 01. Published in final edited form as: Photodiagnosis Photodyn Ther. 2015 December ; 12(4): 561–566. doi:10.1016/j.pdpdt.2015.10.006.
Pre-treatment protoporphyrin IX concentration in actinic keratosis lesions may be a predictive biomarker of response to aminolevulinic-acid based photodynamic therapy SC Kanick1,2,*, SC Davis1,2, Y Zhao1, KL Sheehan3, T Hasan4, EV Maytin4,5, BW Pogue1,2,3,4, and MS Chapman3
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1Thayer 2Norris
School of Engineering, Dartmouth College, Hanover, USA
Cotton Cancer Center, Dartmouth Hitchcock Medical Center, Lebanon NH, USA
3Department 4Wellman
of Surgery, Dartmouth Hitchcock Medical Center, Lebanon, USA
Center for Photomedicine, Massachusetts General Hospital, Boston, USA
5Biomedical
Engineering, Cleveland Clinic, Cleveland USA
Abstract
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Background—Although Aminolevulinic Acid (ALA)-induced protoporphyrin IX (PpIX) photodynamic therapy (PDT) is an effective FDA-approved therapy for actinic keratosis (AK), a substantial fraction of patients (up to 25%) do not respond to treatment. This study examined the feasibility of using pre-treatment measurements of PpIX concentration in AK lesions to predict response of ALA-PpIX PDT. Methods—A non-invasive fiber-optic fluorescence spectroscopy system was used to measure PpIX concentration in patients undergoing standard-of-care ALA-PDT for AK. All patients provided assessments of pain at the time of treatment (n=70), and a subset reported pain and erythema 48–76 hours after treatment (n=13).
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Results—PpIX concentration was significantly higher in lesions of patients reporting high levels of pain (VAS score ≥ 5) immediately after treatment vs. patients reporting pain scores below VAS=5 (p