title: Tumor response and clinical outcome in metastatic gastrointestinal stromal tumors under sunitinib therapy: comparison of RECIST, Choi and volumetric criteria.
abstract: OBJECTIVE
  Purpose of the study was to compare radiological treatment response according to RECIST, Choi and volumetry in GIST-patients under 2nd-line-sunitinib-therapy and to correlate the results of treatment response assessment with disease-specific survival (DSS).
  
  
  METHODS
  20 patients (mean: 60.7 years; 12 male/8 female) with histologically proven GIST underwent baseline-CT of the abdomen under imatinib and follow-up-CTs 3 months and 1 year after change to sunitinib. 68 target lesions (50 hepatic, 18 extrahepatic) were investigated. Therapy response (partial response (PR), stable disease (SD), progressive disease (PD)) was evaluated according to RECIST, Choi and volumetric criteria. Response according to the different assessment systems was compared and correlated to the DSS of the patients utilizing Kaplan-Meier statistics.
  
  
  RESULTS
  The mean DSS (in months) of the response groups 3 months after therapy change was: RECIST: PR (0/20); SD (17/20): 30.4 (months); PD (3/20) 11.6. Choi: PR (10/20) 28.6; SD (8/20) 28.1; PD (2/20) 13.5. Volumetry: PR (4/20) 29.6; SD (11/20) 29.7; PD (5/20) 17.2. Response groups after 1 year of sunitinib showed the following mean DSS: RECIST: PR (3/20) 33.6; SD (9/20) 29.7; PD (8/20) 20.3. Choi: PR (10/20) 21.5; SD (4/20) 42.9; PD (6/20) 23.9. Volumetry: PR (6/20) 27.3; SD (5/20) 38.5; PD (9/20) 19.3.
  
  
  CONCLUSIONS
  One year after modification of therapy, only partial response according to RECIST indicated favorable survival in patients with GIST. The value of alternate response assessment strategies like Choi criteria for prediction of survival in molecular therapy still has to be demonstrated.
authors.affiliation: Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistrasse 15, 81377 Munich, Germany. Nicolai.schramm@med.uni-muenchen.de
authors.forename: N
authors.initials: N
authors.lastname: Schramm
authors.forename: E
authors.initials: E
authors.lastname: Englhart
authors.forename: M
authors.initials: M
authors.lastname: Schlemmer
authors.forename: M
authors.initials: M
authors.lastname: Hittinger
authors.forename: C
authors.initials: C
authors.lastname: Übleis
authors.forename: C R
authors.initials: CR
authors.lastname: Becker
authors.forename: M F
authors.initials: MF
authors.lastname: Reiser
authors.forename: F
authors.initials: F
authors.lastname: Berger
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018572:Disease-Free Survival; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis / Q000188:drug therapy / Q000556:secondary; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007211:Indoles / Q000627:therapeutic use*; D008113:Liver Neoplasms / Q000175:diagnosis / Q000188:drug therapy / Q000556:secondary; D008297:Male; D008875:Middle Aged; D010534:Peritoneal Neoplasms / Q000175:diagnosis / Q000188:drug therapy / Q000556:secondary; D011758:Pyrroles / Q000627:therapeutic use*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000077210:Sunitinib; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D007211:Indoles; D011758:Pyrroles; D000077210:Sunitinib