title: Perfusion CT in patients with metastatic renal cell carcinoma treated with interferon.
abstract: OBJECTIVE
  The objective of our study was to assess the potential value of tumor perfusion parameters measured by perfusion CT as possible biomarkers of prognosis and early indicator of treatment efficacy in patients with metastatic conventional renal cell carcinoma (RCC) treated with interferon.
  
  
  METHODS
  This study comprised 37 patients with metastatic RCC who were enrolled in a larger (n=118) randomized clinical trial of intermediate- versus low-dose interferon. Tumor perfusion parameters-that is, tumor blood flow, blood volume, mean transit time (MTT), and permeability-surface area product-of index metastatic lesions were obtained at baseline and at 8-week follow-up. Baseline perfusion parameters and changes at follow-up were compared, and their associations with patient progression-free survival were estimated. Univariate and multivariate analyses were performed.
  
  
  RESULTS
  Twenty-eight patients were assessable. Median progression-free survival was 5.3 months (95% CI, 2.4-7.4 months), with one partial response. Tumor blood flow at baseline was inversely associated with patient progression-free survival in both univariate (hazard ratio [HR]=1.006, p=0.025) and multivariate (HR=1.007, p=0.012) analyses. There were significant increases in tumor blood flow and reductions in MTT on follow-up scans compared with baseline scans (both, p=0.04), but no association between changes in perfusion parameters and progression-free survival was detected.
  
  
  CONCLUSIONS
  Patients with highly vascularized metastatic RCC as shown by high baseline tumor blood flow appear to have a worse prognosis than those who do not. Tumor perfusion may be a useful biomarker of prognosis and additionally, in the future, may assist in treatment stratification. The potential utility of perfusion CT as an early response indicator was probably inadequately assessed in this study because of the limited antiangiogenic activity of interferon in metastatic RCC.
authors.affiliation: Department of Diagnostic Radiology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Unit 368, Houston, TX 77030-4009, USA. cng@mdanderson.org
authors.forename: Chaan S
authors.initials: CS
authors.lastname: Ng
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
authors.forename: Silvana C
authors.initials: SC
authors.lastname: Faria
authors.forename: E
authors.initials: E
authors.lastname: Lin
authors.forename: Chusilp
authors.initials: C
authors.lastname: Charnsangavej
authors.forename: Nizar M
authors.initials: NM
authors.lastname: Tannir
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000008:administration & dosage / Q000627:therapeutic use*; D016898:Interferon-alpha / Q000008:administration & dosage / Q000627:therapeutic use*; D007668:Kidney / Q000098:blood supply; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D018709:Statistics, Nonparametric; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D007155:Immunologic Factors; D016898:Interferon-alpha