title: MRI and diffusion-weighted MRI to diagnose a local tumour regrowth during long-term follow-up of rectal cancer patients treated with organ preservation after chemoradiotherapy.
abstract: OBJECTIVE
  To assess the value of MRI and diffusion-weighted imaging (DWI) for diagnosing local tumour regrowth during follow-up of organ preservation treatment after chemoradiotherapy for rectal cancer.
  
  
  METHODS
  Seventy-two patients underwent organ preservation treatment (chemoradiotherapy + transanal endoscopic microsurgery or "wait-and-see") and were followed with MRI including DWI (1.5 T) every 3 -months during the first year and 6 months during following years. Two readers scored each MRI for local regrowth using a confidence level, first on standard MRI, then on standard MRI+DWI. Histology and clinical follow-up were the standard reference. Receiver operating characteristic curves were constructed and areas under the curve (AUC) and corresponding accuracy figures calculated on a per-scan basis.
  
  
  RESULTS
  Four hundred and forty MRIs were assessed. Twelve patients developed local regrowth. AUC/sensitivity/specificity for standard MRI were 0.95/58 %/98 % (R1) and 0.96/58 % /100 % (R2). For standard MRI+DWI, these numbers were 0.86/75 %/97 % (R1) and 0.98/75 %/100 % (R2). After adding DWI, the number of equivocal scores decreased from 22 to 7 (R1) and from 40 to 20 (R2).
  
  
  CONCLUSIONS
  Although there was no overall improvement in diagnostic performance in terms of AUC, adding DWI improved the sensitivity of MRI for diagnosing local tumour regrowth and lowered the rate of equivocal MRIs.
  
  
  CONCLUSIONS
  • DWI improves sensitivity for detecting local tumour regrowth after organ preservation treatment. • In particular, DWI can aid in detecting small local recurrence. • DWI reduces the number of equivocal scores.
authors.affiliation: Department of Radiology, Maastricht University Medical Centre+, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands. doenja.lambregts@gmail.com.|Department of Radiology, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, The Netherlands. doenja.lambregts@gmail.com.
authors.forename: Doenja M J
authors.initials: DM
authors.lastname: Lambregts
authors.affiliation: Department of Radiology, Maastricht University Medical Centre+, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.|Department of Radiology, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, The Netherlands.
authors.forename: Max J
authors.initials: MJ
authors.lastname: Lahaye
authors.affiliation: Department of Radiology, Maastricht University Medical Centre+, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.|Department of Surgery, Maastricht University Medical Centre+, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Luc A
authors.initials: LA
authors.lastname: Heijnen
authors.affiliation: Department of Radiology, Maastricht University Medical Centre+, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.|Department of Surgery, Maastricht University Medical Centre+, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Milou H
authors.initials: MH
authors.lastname: Martens
authors.affiliation: Department of Radiology, Maastricht University Medical Centre+, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
authors.forename: Monique
authors.initials: M
authors.lastname: Maas
authors.affiliation: Department of Surgery, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, The Netherlands.|GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre+, P.O. Box 616, 6200 MD, Maastricht, The Netherlands.
authors.forename: Geerard L
authors.initials: GL
authors.lastname: Beets
authors.affiliation: Department of Radiology, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, The Netherlands.|GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre+, P.O. Box 616, 6200 MD, Maastricht, The Netherlands.
authors.forename: Regina G H
authors.initials: RG
authors.lastname: Beets-Tan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D059248:Chemoradiotherapy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology; D009926:Organ Preservation; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D012007:Rectum / Q000000981:diagnostic imaging / Q000473:pathology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: Diffusion; Magnetic resonance imaging; Organ preservation; Rectal neoplasms; Recurrence