title: Ultrasound elastography in patients with rectal cancer treated with chemoradiation.
abstract: OBJECTIVE
  The current literature has described several predictive markers in rectal cancer patients treated with chemoradiation, but so far none of them have been validated for clinical use. The purpose of the present study was to compare quantitative elastography based on ultrasound measurements in the course of chemoradiation with tumor response based on T stage classification and the Mandard tumor regression grading (TRG).
  
  
  METHODS
  We prospectively examined 31 patients with rectal cancer planned for high dose radiochemotherapy. The tumor and the mesorectal fat elasticity were measured using the Acoustic Radiation Force Impulse to generate information on the mechanical properties of the tissue. The objective quantitative elastography shear wave velocity was compared to the T stage classification and TRG.
  
  
  RESULTS
  The baseline mean tumor elasticity was 3.13 m/s. Two and six weeks after the start of chemoradiation the velocities were 2.17 m/s and 2.11 m/s, respectively. The difference between baseline velocity and velocities during the treatment course was statistically significant, (p<0.0001). Patients with tumor confined to the rectal wall at histopathology (ypT1-2) had a mean elasticity measurement after two weeks of treatment of 1.95 m/s, whereas tumors invading the mesorectal fat (ypT3-4) had a velocity of 2.47 m/s, (p<0.05). The mean elasticity tended to be lower (1.99m/s) after two weeks in patients with TRG 1-2 responses in contrast to 2.24 m/s in those with TRG 3-4.
  
  
  CONCLUSIONS
  Ultrasound elastography after two weeks of chemoradiation seems to hold early predictive information to the pathological T stage.
authors: Department of Radiology, DCCG South, Vejle Hospital, 7100 Vejle, Denmark. soeren.rafael.rafaelsen@slb.regionsyddanmark.dk
authors: S R
authors: SR
authors: Rafaelsen
authors: C
authors: C
authors: Vagn-Hansen
authors: T
authors: T
authors: Sørensen
authors: J
authors: J
authors: Lindebjerg
authors: J
authors: J
authors: Pløen
authors: A
authors: A
authors: Jakobsen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome