title: Response evaluation in patients with colorectal liver metastases: RECIST version 1.1 versus modified CT criteria.
abstract: OBJECTIVE
  Our retrospective study compared Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 with modified CT criteria to determine their respective utilities as a prognostic indicator. Using both sets of criteria, we compared treatment responses of patients with colorectal liver metastases treated with bevacizumab-containing chemotherapy with those of patients treated with chemotherapy alone.
  
  
  METHODS
  Fifty-nine patients who received bevacizumab-containing chemotherapy (n=30, group 1) or chemotherapy alone (n=29, group 2) for the treatment of colorectal carcinoma underwent contrast-enhanced CT before treatment and 2 months after treatment. Two radiologists determined changes in tumor size and density between the pretreatment and 2-month follow-up CT images. RECIST 1.1 assesses responses on the basis of changes in tumor size, and the modified CT criteria assesses responses on the basis of changes in tumor density and size. Responses were correlated with time to tumor progression by log rank test.
  
  
  RESULTS
  According to RECIST 1.1, nine of 30 patients (30%) in group 1 and 12 of 29 patients (41%) in group 2 were good responders. According to the modified CT criteria, 23 of 30 patients in group 1 (77%) and 23 of 29 patients in group 2 (79%) were good responders. As assessed by the modified CT criteria, good responders in both groups had significantly longer time to tumor progression than poor responders (p<0.05). As assessed by RECIST 1.1, good responders in group 1 had significantly longer time to tumor progression than poor responders (p=0.0154), but there was no difference in group 2.
  
  
  CONCLUSIONS
  Evaluating treatment response with tumor size and density changes on CT was a better predictor of time to tumor progression than changes in tumor size alone in both groups.
authors.affiliation: Department of Diagnostic Radiology, Institute of Gastroenterology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seodaemun-ku, Shinchon-dong 134, Seoul 120-752, Republic of Korea.
authors.forename: Woo-Suk
authors.initials: WS
authors.lastname: Chung
authors.forename: Mi-Suk
authors.initials: MS
authors.lastname: Park
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Shin
authors.forename: Song-Ee
authors.initials: SE
authors.lastname: Baek
authors.forename: Yeo-Eun
authors.initials: YE
authors.lastname: Kim
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D000068258:Bevacizumab; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology*; D003287:Contrast Media; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007472:Iohexol / Q000031:analogs & derivatives; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D011379:Prognosis
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D003287:Contrast Media; D000068258:Bevacizumab; D007472:Iohexol; C038192:iopromide