title: Revisiting the relationship between tumour volume and diameter in advanced NSCLC patients: An exercise to maximize the utility of each measure to assess response to therapy.
abstract: OBJECTIVE
  To revisit the presumed relationship between tumour diameter and volume in advanced non-small-cell lung cancer (NSCLC) patients, and determine whether the measured volume using volume-analysis software and its proportional changes during therapy matches with the calculated volume obtained from the presumed relationship and results in concordant response assessment.
  
  
  METHODS
  Twenty-three patients with stage IIIB/IV NSCLC with a total of 53 measurable lung lesions, treated in a phase II trial of erlotinib, were studied with institutional review board approval. Tumour volume and diameter were measured at baseline and at the first follow-up computed tomography (CT) examination using volume-analysis software. Using the measured diameter (2r) and the equation, calculated volume was obtained as (4/3)πr(3) at baseline and at the follow-up. Percent volume change was obtained by comparing to baseline for measured and calculated volumes, and response assessment was assigned.
  
  
  RESULTS
  The measured volume was significantly smaller than the calculated volume at baseline (median 11,488.9 mm(3) versus 17,148.6 mm(3); p < 0.0001), with a concordance correlation coefficient (CCC) of 0.7022. At follow-up, the measured volume was once again significantly smaller than the calculated volume (median 6573.5 mm(3) versus 9198.1 mm(3); p = 0.0022), with a CCC of 0.7408. Response assessment by calculated versus measured volume changes had only moderate agreement (weighted κ = 0.545), with discordant assessment results in 20% (8/40) of lesions.
  
  
  CONCLUSIONS
  Calculated volume based on the presumed relationship significantly differed from the measured volume in advanced NSCLC patients, with only moderate concordance in response assessment, indicating the limitations of presumed relationship.
authors.affiliation: Department of Radiology, Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., 75 Francis St., Boston, MA 02215, USA. Electronic address: Mizuki_Nishino@dfci.harvard.edu.
authors.forename: M
authors.initials: M
authors.lastname: Nishino
authors.affiliation: Department of Medical Oncology and Department of Medicine, Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., Boston, MA 02215, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Jackman
authors.affiliation: Department of Radiology, Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., 75 Francis St., Boston, MA 02215, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: DiPiro
authors.affiliation: Department of Radiology, Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., 75 Francis St., Boston, MA 02215, USA.
authors.forename: H
authors.initials: H
authors.lastname: Hatabu
authors.affiliation: Department of Medical Oncology and Department of Medicine, Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., Boston, MA 02215, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Jänne
authors.affiliation: Department of Medical Oncology and Department of Medicine, Dana-Farber Cancer Institute and Brigham and Women's Hospital, 450 Brookline Ave., Boston, MA 02215, USA.
authors.forename: B E
authors.initials: BE
authors.lastname: Johnson
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology*; D003287:Contrast Media; D000069347:Erlotinib Hydrochloride; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007472:Iohexol / Q000031:analogs & derivatives; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology*; D008297:Male; D061330:Multidetector Computed Tomography / Q000379:methods; D009367:Neoplasm Staging; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011799:Quinazolines / Q000627:therapeutic use*; D011856:Radiographic Image Enhancement / Q000379:methods; D015203:Reproducibility of Results; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D003287:Contrast Media; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D007472:Iohexol; C038192:iopromide; D000069347:Erlotinib Hydrochloride