title: Frequent optical imaging during breast cancer neoadjuvant chemotherapy reveals dynamic tumor physiology in an individual patient.
abstract: OBJECTIVE
  Imaging tumor response to neoadjuvant chemotherapy in vivo offers unique opportunities for patient care and clinical decision-making. Detailed imaging studies may allow oncologists to optimize therapeutic drug type and dose based on individual patient response. Most radiologic methods are used sparingly because of cost; thus, important functional information about tumor response dynamics may be missed. In addition, current clinical standards are based on determining tumor size changes; thus, standard anatomic imaging may be insensitive to early or frequent biochemical responses. Because optical methods provide functional imaging end points, our objective is to develop a low-barrier-to-access bedside approach that can be used for frequent, functional assessment of dynamic tumor physiology in individual patients.
  
  
  METHODS
  Diffuse Optical Spectroscopic Imaging (DOSI) is a noninvasive, bedside functional imaging technique that quantifies the concentration and molecular state of tissue hemoglobin, water, and lipid. Pilot clinical studies have shown that DOSI may be a useful tool for quantifying neoadjuvant chemotherapy response, typically by comparing the degree of change in tumor water and deoxy-hemoglobin concentration before and after therapy. Patient responses at 1 week and mid-therapy have been used to predict clinical outcome. In this report, we assess the potential value of frequent DOSI monitoring by performing measurements on 19 different days in a 51-year-old subject with infiltrating ductal carcinoma (initial tumor size 60 x 27 mm) who received neoadjuvant chemotherapy (anthracyclines and bevacizumab) over an 18-week period.
  
  
  RESULTS
  A composite index, the Tissue Optical Index (TOI), showed a significant ( approximately 50%) decrease over the nearly 18 weeks of chemotherapy. Tumor response was sensitive to the type of chemotherapy agent, and functional indices fluctuated in a manner consistent with dynamic tumor physiology. Final pathology revealed 4 mm of residual disease, which was detectible by DOSI at the conclusion of chemotherapy before surgery.
  
  
  CONCLUSIONS
  This case study suggests that DOSI may be a bedside-capable tool for frequent longitudinal monitoring of therapeutic functional response to neoadjuvant chemotherapy.
authors.affiliation: Beckman Laser Institute, University of California, Irvine, 92612, USA. acerussi@uci.edu <acerussi@uci.edu>
authors.forename: Albert E
authors.initials: AE
authors.lastname: Cerussi
authors.forename: Vaya W
authors.initials: VW
authors.lastname: Tanamai
authors.forename: Rita S
authors.initials: RS
authors.lastname: Mehta
authors.forename: David
authors.initials: D
authors.lastname: Hsiang
authors.forename: John
authors.initials: J
authors.lastname: Butler
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Tromberg
mesh_terms: D020533:Angiogenesis Inhibitors / Q000627:therapeutic use; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000188:drug therapy; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000188:drug therapy; D017024:Chemotherapy, Adjuvant; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D019265:Spectroscopy, Near-Infrared
chemical_list: D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab