title: Measurement of tumor volumes improves RECIST-based response assessments in advanced lung cancer.
abstract: OBJECTIVE
  This study was designed to characterize the reproducibility of measurement for tumor volumes and their longest tumor diameters (LDs) and estimate the potential impact of using changes in tumor volumes instead of LDs as the basis for response assessments.
  
  
  METHODS
  We studied patients with advanced lung cancer who have been observed longitudinally with x-ray computed tomography in a multinational trial. A total of 71 time points from 10 patients with 13 morphologically complex target lesions were analyzed. A total of 6461 volume measurements and their corresponding LDs were made by seven independent teams using their own work flows and image analysis tools. Interteam agreement and overall interrater concurrence were characterized.
  
  
  RESULTS
  Interteam agreement between volume measurements was better than between LD measurements (ı = 0.945 vs 0.734, P = .005). The variability in determining the nadir was lower for volumes than for LDs (P = .005). Use of standard thresholds for the RECIST-based method and use of experimentally determined cutoffs for categorizing responses showed that volume measurements had a significantly greater sensitivity for detecting partial responses and disease progression. Earlier detection of progression would have led to earlier changes in patient management in most cases.
  
  
  CONCLUSIONS
  Our findings indicate that measurement of changes in tumor volumes is adequately reproducible. Using tumor volumes as the basis for response assessments could have a positive impact on both patient management and clinical trials. More authoritative work to qualify or discard changes in volume as the basis for response assessments should proceed.
authors.affiliation: Merck Research Laboratories, West Point, PA, USA. mozley@merck.com
authors.forename: P David
authors.initials: PD
authors.lastname: Mozley
authors.forename: Claus
authors.initials: C
authors.lastname: Bendtsen
authors.forename: Binsheng
authors.initials: B
authors.lastname: Zhao
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Schwartz
authors.forename: Matthias
authors.initials: M
authors.lastname: Thorn
authors.forename: Yuanxin
authors.initials: Y
authors.lastname: Rong
authors.forename: Luduan
authors.initials: L
authors.lastname: Zhang
authors.forename: Andrea
authors.initials: A
authors.lastname: Perrone
authors.forename: René
authors.initials: R
authors.lastname: Korn
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Buckler