title: MRI volumetry for prediction of tumour response to neoadjuvant chemotherapy followed by chemoradiotherapy in locally advanced rectal cancer.
abstract: OBJECTIVE
  To investigate if MRI-assessed tumour volumetry correlates with histological tumour response to neoadjuvant chemotherapy (NACT) and subsequent chemoradiotherapy (CRT) in locally advanced rectal cancer (LARC).
  
  
  METHODS
  Data from 69 prospectively enrolled patients with LARC receiving NACT followed by CRT and radical surgery were analysed. Whole-tumour volumes were contoured in T2 weighted MR images obtained pre-treatment (VPRE), after NACT (VNACT) and after the full course of NACT followed by CRT (VCRT). VPRE, VNACT and tumour volume changes relative to VPRE, ΔVNACT and ΔVCRT were calculated and correlated to histological tumour regression grade (TRG).
  
  
  RESULTS
  61% of good histological responders (TRG 1-2) to NACT followed by CRT were correctly predicted by combining VPRE < 10.5 cm(3), ΔVNACT > -78.2% and VNACT < 3.3 cm(3). The highest accuracy was found for VNACT, with 55.1% sensitivity given 100% specificity. The volume regression after completed NACT and CRT (VCRT) was not significantly different between good and poor responders (TRG 1-2 vs TRG 3-5).
  
  
  CONCLUSIONS
  MRI-assessed small tumour volumes after NACT correlated with good histological tumour response (TRG 1-2) to the completed course of NACT and CRT. Furthermore, by combining tumour volume measurements before, during and after NACT, more good responders were identified.
  
  
  CONCLUSIONS
  MRI volumetry may be a tool for early identification of good and poor responders to NACT followed by CRT and surgery in LARC in order to aid more individualized, multimodal treatment.
authors.affiliation: 1 Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Seierstad
authors.affiliation: 1 Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.|2 Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: K H
authors.initials: KH
authors.lastname: Hole
authors.affiliation: 3 Department of Pathology, Oslo University Hospital, Oslo, Norway.
authors.forename: K K
authors.initials: KK
authors.lastname: Grøholt
authors.affiliation: 4 Department of Oncology, Oslo University Hospital, Oslo, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Dueland
authors.affiliation: 2 Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|5 Department of Oncology, Division of Medicine, Akershus University Hospital, Lørenskog, Norway.
authors.forename: A H
authors.initials: AH
authors.lastname: Ree
authors.affiliation: 6 Department of Tumor Biology, Institute For Cancer Research, Oslo University Hospital, Oslo, Norway.|7 Department of Gastroenterological Surgery, Oslo University Hospital, Oslo, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Flatmark
authors.affiliation: 5 Department of Oncology, Division of Medicine, Akershus University Hospital, Lørenskog, Norway.|8 Department of Radiation Biology, Oslo University Hospital, Oslo, Norway.
authors.forename: K R
authors.initials: KR
authors.lastname: Redalen
mesh_terms: D000328:Adult; D000368:Aged; D059248:Chemoradiotherapy; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D060787:Neoplasm Grading; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D047368:Tumor Burden; D055815:Young Adult