title: Comparison of two methods for enumerating circulating tumor cells in carcinoma patients.
abstract: BACKGROUND
  Monitoring of circulating tumor cells (CTCs) in blood of carcinoma patients treated with novel compounds may be a measurement of treatment effectiveness. Before it can be used clinically, a reliably method is needed to enumerate CTCs. We compared two methods for CTC enumeration, OnkoQuick and the CellSearch system.
  
  
  METHODS
  We drew 22.5 ml of blood into three CellSave tubes from 15 healthy donors and 61 patients with metastatic carcinoma. After pooling, 15 ml was processed with OncoQuick and 7.5 ml with CellSearch.
  
  
  RESULTS
  With both methods no CTCs were found in healthy donors. At least one CTC was detected in 14 of 61 patients (23%) with OncoQuick and 33 of 61 patients (54%) with CellSearch (P < 0.0001). The number of CTCs detected was larger for CellSearch (mean 20 CTCs/7.5 ml of blood) than for OncoQuick (3 CTCs/7.5 ml; P < 0.0001).
  
  
  CONCLUSIONS
  The CellSearch system is a more accurate and sensitive method to enumerate CTCs. Further studies are warranted to evaluate CTC enumeration by the CellSearch system as a monitoring tool for the evaluation of the efficacy of novel anticancer agents.
authors.affiliation: Department of Clinical Oncology, University Hospital Graz, Austria. marija.balic@klinikum-graz.at
authors.forename: Marija
authors.initials: M
authors.lastname: Balic
authors.forename: Nadia
authors.initials: N
authors.lastname: Dandachi
authors.forename: Günter
authors.initials: G
authors.lastname: Hofmann
authors.forename: Hellmut
authors.initials: H
authors.lastname: Samonigg
authors.forename: Hans
authors.initials: H
authors.lastname: Loibner
authors.forename: Andreas
authors.initials: A
authors.lastname: Obwaller
authors.forename: Alexander
authors.initials: A
authors.lastname: van der Kooi
authors.forename: Arjan G J
authors.initials: AG
authors.lastname: Tibbe
authors.forename: Gerald V
authors.initials: GV
authors.lastname: Doyle
authors.forename: Leon W M M
authors.initials: LW
authors.lastname: Terstappen
authors.forename: Thomas
authors.initials: T
authors.lastname: Bauernhofer
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy; D002452:Cell Count / Q000379:methods; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D012680:Sensitivity and Specificity