title: Usefulness of magnetic resonance volumetric evaluation in predicting response to preoperative concurrent chemoradiotherapy in patients with resectable rectal cancer.
abstract: OBJECTIVE
  We performed magnetic resonance (MR) volumetry before and after neoadjuvant chemoradiation for evaluating response to therapy in T3 and T4 rectal cancer. To investigate the utility of MR volumetry for predicting the response to neoadjuvant chemoradiation, we compared results from MR volumetry before chemoradiation with those after chemoradiation.
  
  
  METHODS
  A total 112 patients with T3 or T4 rectal cancer who successfully underwent MR volumetry and completed neoadjuvant chemoradiation followed by radical resection for cure were identified. MR volumetries were performed before and after chemoradiation. We compared pre- and postchemoradiation tumor volume and % volume reduction rates of patients whose tumors were down-staged with those of patients that were not down-staged. The same analyses were also performed between those patients having a complete histologic regression and those with residual disease in the operative specimen. We assessed the difference of % volume reduction rate according to Dworak's rectal cancer regression grades.
  
  
  RESULTS
  Fifty-seven patients (50.9%) demonstrated a tumor down-staging after chemoradiation therapy. Both pre- and posttreatment MR tumor volumes were significantly less in patients whose tumors were down-staged than in patients that were not down-staged (p = 0.04, 0.031), and % volume reduction rates were significantly higher in patients whose tumors were down-staged (p = 0.024). Sixteen patients (14.3%) showed pathologically complete tumor regression. The differences of MR tumor volumes before and after chemoradiation and % volume reduction rates were not significantly different between patients having a complete histologic regression and those with residual disease (p = 0.688, 0.451, and 0.480). The differences of % volume reduction rates according to Dworak's grades were statistically significant (p = 0.03).
  
  
  CONCLUSIONS
  The MR volumetric examinations before and after chemoradiation demonstrated the significant difference of tumor volume and % volume reduction rate between patients whose tumors were down-staged and those that were not down-staged. The volume reduction rates were significantly different among groups according to Dworak's grades. However, the MR volumetric evaluation could not identify any differences between those patients having a complete histologic regression and those with residual disease.
authors.affiliation: Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, South Korea.
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Kim
authors.forename: Dae Yong
authors.initials: DY
authors.lastname: Kim
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Kim
authors.forename: Kyung Hae
authors.initials: KH
authors.lastname: Jung
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Chang
authors.forename: Seung-Yong
authors.initials: SY
authors.lastname: Jeong
authors.forename: Dae Kyung
authors.initials: DK
authors.lastname: Sohn
authors.forename: Hyo Seong
authors.initials: HS
authors.lastname: Choi
authors.forename: Joong Bae
authors.initials: JB
authors.lastname: Ahn
authors.forename: Dae Hyun
authors.initials: DH
authors.lastname: Kim
authors.forename: Seok-Byung
authors.initials: SB
authors.lastname: Lim
authors.forename: Jong Seok
authors.initials: JS
authors.lastname: Lee
authors.forename: Jae-Gahb
authors.initials: JG
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery