title: Endoscopic ultrasound and magnetic resonance imaging for re-staging rectal cancer after radiotherapy.
abstract: OBJECTIVE
  To compare the sensitivity and specificity of two imaging techniques, endoscopic ultrasound (EUS) and magnetic resonance imaging (MRI), in patients with rectal cancer after neoadjuvant chemoradiation therapy. And we compared EUS and MRI data with histological findings from surgical specimens.
  
  
  METHODS
  Thirty-nine consecutive patients (51.3% Male; mean age: 68.2 +/- 8.9 years) with histologically confirmed distal rectal cancer were examined for staging. All patients underwent EUS and MRI imaging before and after neoadjuvant chemoradiation therapy.
  
  
  RESULTS
  After neoadjuvant chemoradiation, EUS and MRI correctly classified 46% (18/39) and 44% (17/39) of patients, respectively, in line with their histological T stage (P > 0.05). These proportions were higher for both techniques when nodal involvement was considered: 69% (27/39) and 62% (24/39). When patients were sorted into T and N subgroups, the diagnostic accuracy of EUS was better than MRI for patients with T0-T2 (44% vs 33%, P > 0.05) and N0 disease (87% vs 52%, P = 0.013). However, MRI was more accurate than EUS in T and N staging for patients with more advanced disease after radiotherapy, though these differences did not reach statistical significance.
  
  
  CONCLUSIONS
  EUS and MRI are accurate imaging techniques for staging rectal cancer. However, after neoadjuvant RT-CT, the role of both methods in the assessment of residual rectal tumors remains uncertain.
authors: Gastroenterology and Gastrointestinal Endoscopy Unit, IRCCS Vita-Salute University, San Raffaele Scientific Institute, Milan, Italy. mezzi.gianni@hsr.it
authors: Gianni
authors: G
authors: Mezzi
authors: Paolo Giorgio
authors: PG
authors: Arcidiacono
authors: Silvia
authors: S
authors: Carrara
authors: Francesco
authors: F
authors: Perri
authors: Maria Chiara
authors: MC
authors: Petrone
authors: Francesco
authors: F
authors: De Cobelli
authors: Simone
authors: S
authors: Gusmini
authors: Carlo
authors: C
authors: Staudacher
authors: Alessandro
authors: A
authors: Del Maschio
authors: Pier Alberto
authors: PA
authors: Testoni
mesh_terms: D000368:Aged; D003131:Combined Modality Therapy / Q000379:methods; D019160:Endosonography / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging / Q000379:methods*; D011379:Prognosis; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods