title: Diffusion-weighted magnetic resonance imaging for pretreatment prediction and monitoring of treatment response of patients with locally advanced breast cancer undergoing neoadjuvant chemotherapy.
abstract: BACKGROUND
  For patients with locally advanced breast cancer (LABC) undergoing neoadjuvant chemotherapy (NACT), the European Guidelines for Breast Imaging recommends magnetic resonance imaging (MRI) to be performed before start of NACT, when half of the NACT has been administered and prior to surgery. This is the first study addressing the value of flow-insensitive apparent diffusion coefficients (ADCs) obtained from diffusion-weighted (DW) MRI at the recommended time points for pretreatment prediction and monitoring of treatment response.
  
  
  METHODS
  Twenty-five LABC patients were included in this prospective study. DW MRI was performed using single-shot spin-echo echo-planar imaging with b-values of 100, 250 and 800 s/mm(2) prior to NACT, after four cycles of NACT and at the conclusion of therapy using a 1.5 T MR scanner. ADC in the breast tumor was calculated from each assessment. The strength of correlation between pretreatment ADC, ADC changes and tumor volume changes were examined using Spearman's rho correlation test.
  
  
  RESULTS
  Mean pretreatment ADC was 1.11 + or - 0.21 x 10(-3) mm(2)/s. After 4 cycles of NACT, ADC was significantly increased (1.39 + or - 0.36 x 10(-3) mm(2)/s; p=0.018). There was no correlation between individual pretreatment breast tumor ADC and MR response measured after four cycles of NACT (p=0.816) or prior to surgery (p=0.620).
  
  
  CONCLUSIONS
  Pretreatment tumor ADC does not predict treatment response for patients with LABC undergoing NACT. Furthermore, ADC increase observed mid-way in the course of NACT does not correlate with tumor volume changes.
authors.affiliation: Institute for Cancer Research, Oslo University Hospital, Norway. line.nilsen2@rr-research.no
authors.forename: Line
authors.initials: L
authors.lastname: Nilsen
authors.forename: Anne
authors.initials: A
authors.lastname: Fangberget
authors.forename: Oliver
authors.initials: O
authors.lastname: Geier
authors.forename: Dag Rune
authors.initials: DR
authors.lastname: Olsen
authors.forename: Therese
authors.initials: T
authors.lastname: Seierstad
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology* / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016896:Treatment Outcome