title: Metabolic response to preoperative chemotherapy predicts prognosis for patients undergoing surgical resection of colorectal cancer metastatic to the liver.
abstract: BACKGROUND
  Biological characteristics of colorectal cancer liver metastases (CRCLM) are increasingly recognized as major determinants of patient outcome. The purpose of this study was to evaluate the prognostic value of metabolic response to preoperative chemotherapy as quantified by (18)F-FDG positron emission tomography (PET) for patients undergoing liver resection of CRCLM.
  
  
  METHODS
  All patients (n = 80) who had staging PET before liver resection for CRCLM at Austin Health in Melbourne between 2004 and 2011 were included. Thirty-seven patients had PET and CT imaging before and after preoperative chemotherapy. Semiquantitative PET parameters-maximum standardized uptake variable (SUVmax), metabolic tumour volume (MTV), and total glycolytic volume (TGV)-were derived. Metabolic response was determined by the proportional change in PET parameters (∆SUVmax, ∆MTV, ∆TGV). Prognostic scores, CT RECIST response, and tumour regression grading (TRG) were also assessed. Correlation to recurrence-free (RFS) and overall survival (OS) was assessed using Kaplan-Meier survival and multivariate analysis.
  
  
  RESULTS
  Semiquantitative parameters on staging PET before chemotherapy were not predictive of prognosis, whereas all parameters after chemotherapy were prognostic for RFS and OS. Only ∆SUVmax was predictive of RFS and OS on multivariate analysis. Patients with metabolically responsive tumours had an OS of 86 % at 3 years vs. 38 % with nonresponsive or progressive tumours (p = 0.003). RECIST and TRG did not predict outcome.
  
  
  CONCLUSIONS
  Tumour metabolic response to preoperative chemotherapy as quantified by PET is predictive of prognosis in patients undergoing resection of CRCLM. Assessing metabolic response uniquely characterizes tumour biology, which may allow future optimization of patient and treatment selection.
authors.affiliation: Department of Surgery, Austin Hospital, University of Melbourne, Heidelberg, VIC, Australia, lawrencel@unimelb.edu.au.
authors.forename: Lawrence F
authors.initials: LF
authors.lastname: Lau
authors.forename: David S
authors.initials: DS
authors.lastname: Williams
authors.forename: Sze Ting
authors.initials: ST
authors.lastname: Lee
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Scott
authors.forename: Christopher
authors.initials: C
authors.lastname: Christophi
authors.forename: Vijayaragavan
authors.initials: V
authors.lastname: Muralidharan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D003131:Combined Modality Therapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D005472:Fluorouracil / Q000008:administration & dosage; D005500:Follow-Up Studies; D006498:Hepatectomy; D006801:Humans; D002955:Leucovorin / Q000008:administration & dosage; D008113:Liver Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000556:secondary / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D000077150:Oxaliplatin; D049268:Positron-Emission Tomography; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D019275:Radiopharmaceuticals; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D009944:Organoplatinum Compounds; D019275:Radiopharmaceuticals; D000077150:Oxaliplatin; D019788:Fluorodeoxyglucose F18; D002955:Leucovorin; D005472:Fluorouracil