title: Predicting response to breast cancer neoadjuvant chemotherapy using diffuse optical spectroscopy.
abstract: Diffuse optical spectroscopy (DOS) and imaging are emerging diagnostic techniques that quantitatively measure the concentration of deoxy-hemoglobin (ctHHb), oxy-hemoglobin (ctO(2)Hb), water (ctH(2)O), and lipid in cm-thick tissues. In early-stage clinical studies, diffuse optical imaging and DOS have been used to characterize breast tumor biochemical composition and monitor therapeutic response in stage II/III neoadjuvant chemotherapy patients. We investigated whether DOS measurements obtained before and 1 week into a 3-month adriamycin/cytoxan neoadjuvant chemotherapy regimen can predict final, postsurgical pathological response. Baseline DOS measurements of 11 patients before therapy revealed significant increases in tumor ctHHb, ctO(2)Hb, ctH(2)O, and spectral scattering slope, and decreases in bulk lipids, relative to normal breast tissue. Tumor concentrations of ctHHb, ctO(2)Hb, and ctH(2)O dropped 27 +/- 15%, 33 +/- 7%, and 11 +/- 15%, respectively, within 1 week (6.5 +/- 1.4 days) of the first treatment for pathology-confirmed responders (n = 6), whereas nonresponders (n = 5) and normal side controls showed no significant changes in these parameters. The best single predictor of therapeutic response 1 week posttreatment was ctHHb (83% sensitivity, 100% specificity), while discrimination analysis based on combined ctHHb and ctH(2)O changes classified responders vs. nonresponders with 100% sensitivity and specificity. In addition, the pretreatment tumor-to-normal ctO(2)Hb ratio was significantly higher in responders (2.82 +/- 0.44) vs. nonresponders (1.82 +/- 0.49). These results highlight DOS sensitivity to tumor cellular metabolism and biochemical composition and demonstrate its potential for predicting and monitoring an individual's response to treatment.
authors.affiliation: Laser Medical and Microbeam Program, Beckman Laser Institute and Medical Clinic, University of California-Irvine, 1002 Health Sciences Road East, Irvine, CA 92612, USA. acerussi@uci.edu
authors.forename: Albert
authors.initials: A
authors.lastname: Cerussi
authors.forename: David
authors.initials: D
authors.lastname: Hsiang
authors.forename: Natasha
authors.initials: N
authors.lastname: Shah
authors.forename: Rita
authors.initials: R
authors.lastname: Mehta
authors.forename: Amanda
authors.initials: A
authors.lastname: Durkin
authors.forename: John
authors.initials: J
authors.lastname: Butler
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Tromberg
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D017024:Chemotherapy, Adjuvant / Q000379:methods; D005260:Female; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared; D013057:Spectrum Analysis; D016896:Treatment Outcome
chemical_list: D008055:Lipids