title: Diffusion-weighted imaging reflects pathological therapeutic response and relapse in breast cancer.
abstract: BACKGROUND
  Conventional imaging does not always accurately depict the pathological response to neoadjuvant chemotherapy (NAC). Diffusion-weighted imaging (DWI) may provide additional insight into the chemotherapeutic effect. This study assessed whether the apparent diffusion coefficient (ADC) correlated with pathological outcome and prognosis in breast cancer patients receiving NAC.
  
  
  METHODS
  Fifty-six patients with locally advanced breast cancer received surgery after NAC. Dynamic contrast-enhanced (DCE) and DWI were performed before and after NAC. The pathological response was classified into five categories from no response to complete response according to amount of residual cancer. The correlation between ADC and postoperative pathologic and prognostic outcome was assessed.
  
  
  RESULTS
  The distribution of the pathological response classification was as follows: no response, 3 cases; mild response, 22 cases; moderate response, 12 cases; marked response, 11 cases; complete response, 8 cases. ADC after NAC correlated with pathological response, but ADC before NAC did not. The change in ADC after chemotherapy had better correlation coefficient (r = 0.67) than change in size (r = 0.58) and ADC after NAC (r = 0.64). Although the group with larger change of tumor size showed only marginal significance compared with the smaller change group (p = 0.089), the group with higher change of ADC showed significantly better prognosis than the lower one (p = 0.038).
  
  
  CONCLUSIONS
  Change in ADC after chemotherapy better correlated with pathological outcome and prognosis than change in tumor size. DWI has potential in evaluating the pathological outcome of NAC in breast cancer patients.
authors: Department of General Surgery, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba, 260-0856, Japan, hifujimonty@chiba-u.jp.
authors: Hiroshi
authors: H
authors: Fujimoto
authors: Toshiki
authors: T
authors: Kazama
authors: Takeshi
authors: T
authors: Nagashima
authors: Masahiro
authors: M
authors: Sakakibara
authors: Tiberiu Hiroshi
authors: TH
authors: Suzuki
authors: Yoshiyuki
authors: Y
authors: Okubo
authors: Nobumitsu
authors: N
authors: Shiina
authors: Kaoru
authors: K
authors: Fujisaki
authors: Satoshi
authors: S
authors: Ota
authors: Masaru
authors: M
authors: Miyazaki
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology* / Q000601:surgery; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D016896:Treatment Outcome