title: Changes in primary breast cancer heterogeneity may augment midtreatment MR imaging assessment of response to neoadjuvant chemotherapy.
abstract: OBJECTIVE
  To evaluate whether changes in magnetic resonance (MR) imaging heterogeneity may aid assessment for pathologic complete response (pCR) to neoadjuvant chemotherapy (NACT) in primary breast cancer and to compare pCR with standard Response Evaluation Criteria in Solid Tumors response.
  
  
  METHODS
  Institutional review board approval, with waiver of informed consent, was obtained for this retrospective analysis of 36 consecutive female patients, with unilateral unifocal primary breast cancer larger than 2 cm in diameter who were receiving sequential anthracycline-taxane NACT between October 2008 and October 2012. T2- and T1-weighted dynamic contrast material-enhanced MR imaging was performed before, at midtreatment (after three cycles), and after NACT. Changes in tumor entropy (irregularity) and uniformity (gray-level distribution) were determined before and after MR image filtration (for different-sized features). Entropy and uniformity for pathologic complete responders and nonresponders were compared by using the Mann-Whitney U test and receiver operating characteristic analysis.
  
  
  RESULTS
  With NACT, there was an increase in uniformity and a decrease in entropy on T2-weighted and contrast-enhanced subtracted T1-weighted MR images for all filters (uniformity: 23.45% and 22.62%; entropy: -19.15% and -19.26%, respectively). There were eight complete pathologic responders. An area under the curve of 0.84 for T2-weighted MR imaging entropy and uniformity (P = .004 and .003) and 0.66 for size (P = .183) for pCR was found, giving a sensitivity and specificity of 87.5% and 82.1% for entropy and 87.5% and 78.6% for uniformity compared with 50% and 82.1%, respectively, for tumor size change for association with pCR.
  
  
  CONCLUSIONS
  Tumors become more homogeneous with treatment. An increase in T2-weighted MR imaging uniformity and a decrease in T2-weighted MR imaging entropy following NACT may provide an earlier indication of pCR than tumor size change.
authors.affiliation: From the Departments of Radiology (J.P., H.V., V.G.), Clinical Oncology (J.G., A.T.), and Medical Oncology (J.M., M.H.), Guys and St Thomas' Hospitals NHS Foundation Trust, Westminster Bridge Road, London SE1 7EH, England; Division of Imaging Sciences and Biomedical Engineering, King's College, London, England (M.S., G.C., V.G.); and Institute of Nuclear Medicine, University College London, London, England (B.G.).
authors.forename: Jyoti
authors.initials: J
authors.lastname: Parikh
authors.forename: Mariyah
authors.initials: M
authors.lastname: Selmi
authors.forename: Geoff
authors.initials: G
authors.lastname: Charles-Edwards
authors.forename: Jennifer
authors.initials: J
authors.lastname: Glendenning
authors.forename: Balaji
authors.initials: B
authors.lastname: Ganeshan
authors.forename: Hema
authors.initials: H
authors.lastname: Verma
authors.forename: Janine
authors.initials: J
authors.lastname: Mansi
authors.forename: Mark
authors.initials: M
authors.lastname: Harries
authors.forename: Andrew
authors.initials: A
authors.lastname: Tutt
authors.forename: Vicky
authors.initials: V
authors.lastname: Goh
mesh_terms: D000328:Adult; D000368:Aged; D018943:Anthracyclines / Q000008:administration & dosage; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D003287:Contrast Media; D000077143:Docetaxel; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012984:Software; D013382:Subtraction Technique; D043823:Taxoids / Q000008:administration & dosage; D000068878:Trastuzumab; D016896:Treatment Outcome
chemical_list: D018943:Anthracyclines; D061067:Antibodies, Monoclonal, Humanized; D003287:Contrast Media; D043823:Taxoids; D000077143:Docetaxel; D000068878:Trastuzumab