title: Morphology, Attenuation, Size, and Structure (MASS) criteria: assessing response and predicting clinical outcome in metastatic renal cell carcinoma on antiangiogenic targeted therapy.
abstract: OBJECTIVE
  The objective of our study was to evaluate response assessment and predict clinical outcome in patients with metastatic renal cell carcinoma (RCC) receiving antiangiogenic targeted therapy. Target lesions were assessed on routine contrast-enhanced CT (CECT) images obtained during the portal venous phase using new response criteria.
  
  
  METHODS
  Standard CECT examinations of patients with metastatic clear cell RCC on first-line sunitinib or sorafenib therapy (n = 84) were retrospectively evaluated using Mass, Attenuation, Size, and Structure (MASS) Criteria; Response Evaluation Criteria in Solid Tumors (RECIST); Size and Attenuation CT (SACT) Criteria; and modified Choi Criteria. The objective response to therapy was compared with clinical outcomes including time to progression (TTP) and disease-specific survival. The Kaplan-Meier method was used to estimate survival functions.
  
  
  RESULTS
  A favorable response according to MASS Criteria had a sensitivity of 86% and specificity of 100% in identifying patients with a good clinical outcome (i.e., progression-free survival of > 250 days) versus 17% and 100%, respectively, for RECIST partial response. The objective categories of response used by MASS Criteria-favorable response, indeterminate response, and unfavorable response-differed significantly from one another with respect to TTP (p < 0.0001, log-rank test) and disease-specific survival (p < 0.0001, log-rank test).
  
  
  CONCLUSIONS
  Assessment of metastatic RCC target lesions on CECT for changes in morphology, attenuation, size, and structure by MASS Criteria is more accurate than response assessment by SACT Criteria, RECIST, or modified Choi Criteria. Furthermore, the use of MASS Criteria for imaging response assessment showed high interobserver agreement and may predict disease outcome in patients with metastatic RCC on targeted therapy.
authors.affiliation: Imaging Institute, Cleveland Clinic, Cleveland, OH 44195, USA. smithmdphd@yahoo.com
authors.forename: Andrew Dennis
authors.initials: AD
authors.lastname: Smith
authors.forename: Shetal N
authors.initials: SN
authors.lastname: Shah
authors.forename: Brian I
authors.initials: BI
authors.lastname: Rini
authors.forename: Michael L
authors.initials: ML
authors.lastname: Lieber
authors.forename: Erick M
authors.initials: EM
authors.lastname: Remer
mesh_terms: D000328:Adult; D000368:Aged; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D001557:Benzenesulfonates / Q000008:administration & dosage / Q000627:therapeutic use*; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D006801:Humans; D007211:Indoles / Q000008:administration & dosage / Q000627:therapeutic use*; D007472:Iohexol / Q000031:analogs & derivatives; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D011725:Pyridines / Q000008:administration & dosage / Q000627:therapeutic use*; D011758:Pyrroles / Q000008:administration & dosage / Q000627:therapeutic use*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D000077157:Sorafenib; D000077210:Sunitinib; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D020533:Angiogenesis Inhibitors; D001557:Benzenesulfonates; D003287:Contrast Media; D007211:Indoles; D010671:Phenylurea Compounds; D011725:Pyridines; D011758:Pyrroles; D009536:Niacinamide; D007472:Iohexol; C038192:iopromide; D000077157:Sorafenib; D000077210:Sunitinib