title: FDG-PET assessment of rectal cancer response to neoadjuvant chemoradiotherapy is not associated with long-term prognosis: a prospective evaluation.
abstract: BACKGROUND
  At present there is no defined role for routine FDG-PET in the preoperative evaluation of nonmetastatic rectal cancer.
  
  
  OBJECTIVE
  The primary objective of this study was to evaluate the ability of FDG-PET to predict long-term prognosis based on the response to neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer.
  
  
  METHODS
  This was a prospective study.
  
  
  METHODS
  This study was performed at an academic, tertiary care, comprehensive cancer center.
  
  
  METHODS
  One hundred twenty-seven patients with locally advanced rectal cancer were enrolled between September 1999 and December 2005.
  
  
  METHODS
  All patients underwent FDG-PET scans before and after neoadjuvant chemoradiotherapy.
  
  
  METHODS
  FDG-PET parameters were evaluated by at least 2 study board-certified nuclear medicine physicians, and included mean standard uptake value, maximum standard uptake value, total lesion glycolysis, and visual response score. The main outcome measures were time to recurrence and disease-specific survival.
  
  
  RESULTS
  Of 127 patients, 82 (65%) were men, the median age was 60 years (range, 27-82), 110 patients had stage II/III disease, and 17 patients had stage IV disease. Median follow-up among survivors was 77 months (range, 1-115 months). Nine patients had unresectable metastatic disease and were excluded from the time-to-recurrence analysis. At 5 years, 74% (95% CI = 66%-81%) of patients had not had recurrences (locally and/or distantly). The 5-year disease-specific survival was 89% (95% CI = 81%-93%). On univariate analysis, visual response score and time to recurrence came closest to having an association (HR = 0.83, 95% CI = 0.68-1.01, p = 0.06). On multivariate analysis, the visual response score was not significant (p = 0.85). No FDG-PET parameter was associated with disease-specific survival.
  
  
  CONCLUSIONS
  Assessment of rectal cancer response to neoadjuvant chemoradiotherapy by FDG-PET provides no prognostic information. Therefore, serial FDG-PET before and after neoadjuvant chemoradiotherapy should not be performed for this purpose.
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: Jeannine A
authors.initials: JA
authors.lastname: Ruby
authors.forename: Tobias
authors.initials: T
authors.lastname: Leibold
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Akhurst
authors.forename: Jinru
authors.initials: J
authors.lastname: Shia
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Saltz
authors.forename: Madhu
authors.initials: M
authors.lastname: Mazumdar
authors.forename: Elyn R
authors.initials: ER
authors.lastname: Riedel
authors.forename: Steven M
authors.initials: SM
authors.lastname: Larson
authors.forename: José G
authors.initials: JG
authors.lastname: Guillem
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059248:Chemoradiotherapy / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18