title: Real-time assessment of intraperitoneal tumor growth in a rat model using CEA immunoscintigraphy.
abstract: BACKGROUND
  In most preclinical models, assessment of intraperitoneal tumor location and size require killing the animal. The dynamics of postoperative intraperitoneal tumor implantation and growth remain unclear. A noninvasive method allowing reliable in vivo, real-time assessment of tumor growth is desirable.
  
  
  METHODS
  An intraperitoneal tumor homograft using cultured CC531 colorectal cells was created by laparotomy in 24 Wistar Albino Glaxo rats. Eight additional rats were used as controls. Then, 10 MBq technetium 99m-labeled anticarcinoembryonic antigen (anti-CEA) monoclonal antibodies were administrated intravenously and radioactivity uptake was measured by using extracorporeal gamma counting at various time points. Subsequently, the animals were killed for tumor weighting. In 2 more groups of 8 animals, real-time, repeated measures were performed.
  
  
  RESULTS
  Correlation between gamma counting and tumor weight was highly significant (P <.001). The regression equation obtained by using the least squares method was: tumor weight (g) = 2.422 + 0.267 x counts. It was possible to obtain real-time tumor growth curves when repeated measurements of radioactivity were performed. At day 25, the predicted tumor weight was 8.49 +/- 0.76 g, the measured weight was 8.16 +/- 0.99 g.
  
  
  CONCLUSIONS
  Immunoscintigraphic measurements with technetium 99m anti-CEA antibodies are highly correlated with tumor weight in this model. As opposed to other tumor graft models based on autopsy findings, real-time monitoring is possible. This will allow dynamic studies of intraperitoneal tumor implantation and growth and will reduce the number of animals used in further studies.
authors.affiliation: Department of Surgery, Institute of Pathology, Otto-von-Guericke University, Leipziger Strasse 44, D-39120 Magdeburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Pross
authors.forename: H U
authors.initials: HU
authors.lastname: Schulz
authors.forename: T
authors.initials: T
authors.lastname: Günther
authors.forename: K
authors.initials: K
authors.lastname: Hönl
authors.forename: R
authors.initials: R
authors.lastname: Mantke
authors.forename: A
authors.initials: A
authors.lastname: Koch
authors.forename: W
authors.initials: W
authors.lastname: Halangk
authors.forename: M A
authors.initials: MA
authors.lastname: Reymond
authors.forename: H
authors.initials: H
authors.lastname: Lippert
mesh_terms: D000818:Animals; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D004195:Disease Models, Animal; D008297:Male; D010534:Peritoneal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D016719:Radioimmunodetection; D051381:Rats; D014407:Tumor Cells, Cultured
chemical_list: D002272:Carcinoembryonic Antigen