title: Interlesion differences in the local photodynamic therapy response of oral cavity lesions assessed by diffuse optical spectroscopies.
abstract: Photodynamic therapy (PDT) efficacy depends on the local dose deposited in the lesion as well as oxygen availability in the lesion. We report significant interlesion differences between two patients with oral lesions treated with the same drug dose and similar light dose of 2-1[hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH)-mediated photodynamic therapy (PDT). Pre-PDT and PDT-induced changes in hemodynamic parameters and HPPH photosensitizer content, quantified by diffuse optical methods, demonstrated substantial differences between the two lesions. The differences in PDT action determined by the oxidative cross-linking of signal transducer and activator of transcription 3 (STAT3), a molecular measure of accumulated local PDT photoreaction, also showed >100-fold difference between the lesions, greatly exceeding what would be expected from the slight difference in light dose. Our results suggest diffuse optical spectroscopies can provide in vivo metrics that are indicative of local PDT dose in oral lesions.
authors.affiliation: Department of Cell Stress Biology & PDT Center, Roswell Park Cancer Institute, Elm & Carlton St, Buffalo, NY 14263,  USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Rohrbach
authors.forename: Nestor
authors.initials: N
authors.lastname: Rigual
authors.forename: Erin
authors.initials: E
authors.lastname: Tracy
authors.forename: Andrew
authors.initials: A
authors.lastname: Kowalczewski
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Keymel
authors.forename: Michele T
authors.initials: MT
authors.lastname: Cooper
authors.forename: Weirong
authors.initials: W
authors.lastname: Mo
authors.forename: Heinz
authors.initials: H
authors.lastname: Baumann
authors.forename: Barbara W
authors.initials: BW
authors.lastname: Henderson
authors.forename: Ulas
authors.initials: U
authors.lastname: Sunar