title: MRI tumor volume reduction rate vs tumor regression grade in the pre-operative re-staging of locally advanced rectal cancer after chemo-radiotherapy.
abstract: OBJECTIVE
  To compare tumor volume reduction rate (TVRR) measured by MR volumetry after preoperative chemoradiotherapy (CRT) and pathological tumor regression grade (TRG) in locally advanced rectal cancer (LARC).
  
  
  METHODS
  In total, 20 patients with LARC (cT3-T4) treated with CRT followed by Total Mesorectal Excision (TME) between April 2011 and April 2013 were analyzed retrospectively. Pre- and post- CRT tumor volumes (MR volumetry) were measured on 3D MR sequences. TVRR was determined using the equation TVRR (%)=(pre-CRT tumor volume-post-CRT tumor volume)×100/pre-CRT tumor volume. The downstaging (defined as ypT0-T2) of tumor mass was evaluated and the correlation between TVRR and TRG was calculated with the method proposed by Dworak using the Spearman rank test.
  
  
  RESULTS
  The median TVRR was 77.3% (range, 26.4-99.3%); TVRR was >60% in 18 cases (90%) and in 8 of these patients (44.4 %) it was >80%. Downstaging of tumor lesions was obtained in 15 patients (75%). In 4 cases there was a complete tumor regression (TRG4) at histological examination and in the same patients there was also a TVRR>80% measured by MR volumetry. A statistically significant correlation between TVRR and TRG (r(s)=0.5466, p=0.0126) was observed.
  
  
  CONCLUSIONS
  TVRR after preoperative CRT correlates with TRG in LARC. The MR volumetry is a prognostic factor to estimate the tumor response after preoperative CRT. TVRR data may be an useful biomarker for tailoring surgery and postoperative adjuvant chemotherapy.
authors.affiliation: Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Unit of Diagnostic and Interventional Radiology, Pisa University Hospital, Italy. Electronic address: emanuele.neri@med.unipi.it.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Neri
authors.affiliation: Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Unit of Diagnostic and Interventional Radiology, Pisa University Hospital, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Guidi
authors.affiliation: Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Unit of Diagnostic and Interventional Radiology, Pisa University Hospital, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Pancrazi
authors.affiliation: Unit of Anatomy and Pathology, Pisa University Hospital, Italy.
authors.forename: Maura
authors.initials: M
authors.lastname: Castagna
authors.affiliation: Unit of Anatomy and Pathology, Pisa University Hospital, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Castelluccio
authors.affiliation: Unit of Colorectal Surgery, Pisa University Hospital, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Balestri
authors.affiliation: Unit of Colorectal Surgery, Pisa University Hospital, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Buccianti
authors.affiliation: Unit of Oncology, Pisa University Hospital, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Masi
authors.affiliation: Unit of Oncology, Pisa University Hospital, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Falcone
authors.affiliation: Unit of Radiotherapy, Pisa University Hospital, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Manfredi
authors.affiliation: Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Unit of Diagnostic and Interventional Radiology, Pisa University Hospital, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Faggioni
authors.affiliation: Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Unit of Diagnostic and Interventional Radiology, Pisa University Hospital, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Bartolozzi
mesh_terms: D000328:Adult; D000368:Aged; D059248:Chemoradiotherapy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011300:Preoperative Care / Q000379:methods*; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D012189:Retrospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: Image processing; MR; Quantitative imaging; Rectal cancer; Staging