title: Is the standardized uptake value of FDG-PET/CT predictive of pathological complete response in locally advanced rectal cancer treated with capecitabine-based neoadjuvant chemoradiation?
abstract: OBJECTIVE
  Our aim was to assess FDG-PET/CT as a surrogate biomarker of the pathological complete response in locally advanced rectal cancer treated with neoadjuvant chemoradiation.
  
  
  METHODS
  T3-4 and/or N+ rectal cancer patients were treated prospectively with capecitabine-based chemoradiation and total mesorectal excision 7-8 weeks later. FDG-PET/CT uptake was obtained at baseline, after 2 weeks, and 6 weeks following treatment completion, calculating the maximum standardized uptake value (SUV) and percentage difference to identify the early and late metabolic 'response index'.
  
  
  RESULTS
  Thirty-one patients were treated from January 2009 to January 2012 at the Istituto Nazionale dei Tumori of Milan. One patient was excluded due to surgery refusal. The pathological complete response rate was 30%. Early FDG-PET/CT was performed in 24 consenting patients and failed to show predictive utility. On the contrary, significant differences in late SUV value and response index were observed between complete and noncomplete pathological responders (p = 0.0006 and 0.03). In multivariate analysis including most relevant SUV parameters, none of them was independently associated with a pathological complete response. With receiver operating characteristic curve analysis, a late SUV threshold <5.4 had 81% sensitivity and 100% specificity, with 90% overall accuracy.
  
  
  CONCLUSIONS
  We evidenced a possible predictive role of late FDG-PET/CT for the assessment of pathological response in locally advanced rectal cancer following neoadjuvant chemoradiation.
authors: Department of Nuclear Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors: Chiara
authors: C
authors: Bampo
authors: Alessandra
authors: A
authors: Alessi
authors: Simona
authors: S
authors: Fantini
authors: Gaia
authors: G
authors: Bertarelli
authors: Filippo
authors: F
authors: de Braud
authors: Emilio
authors: E
authors: Bombardieri
authors: Francesca
authors: F
authors: Valvo
authors: Flavio
authors: F
authors: Crippa
authors: Maria
authors: M
authors: Di Bartolomeo
authors: Luigi
authors: L
authors: Mariani
authors: Massimo
authors: M
authors: Milione
authors: Pamela
authors: P
authors: Biondani
authors: Barbara
authors: B
authors: Avuzzi
authors: Chiara
authors: C
authors: Chiruzzi
authors: Filippo
authors: F
authors: Pietrantonio
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D000069287:Capecitabine; D059248:Chemoradiotherapy; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D019788:Fluorodeoxyglucose F18; D005472:Fluorouracil / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000592:standards; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012004:Rectal Neoplasms / Q000188:drug therapy* / Q000473:pathology* / Q000532:radiotherapy*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D000964:Antimetabolites, Antineoplastic; D019275:Radiopharmaceuticals; D003841:Deoxycytidine; D019788:Fluorodeoxyglucose F18; D000069287:Capecitabine; D005472:Fluorouracil