Noninvasive monitoring of colonic carcinogenesis: feasibility of [18F]FDG-PET in the azoxymethane model

van Kouwen, Mariëtte C.A.; Laverman, Peter; van Krieken, J. Han J.M.; Oyen, Wim J.G.; Nagengast, Fokko M.; Drenth, Joost P.H.

doi:10.1016/j.nucmedbio.2005.11.003

« Previous Next »Nuclear Medicine and Biology
Volume 33, Issue 2 , Pages 245-248, February 2006

Noninvasive monitoring of colonic carcinogenesis: feasibility of [¹⁸F]FDG-PET in the azoxymethane model

Mariëtte C.A. van Kouwen
- Department of Gastroenterology, Radboud University Nijmegen Medical Center, Nijmegen, 6500 HB Nijmegen, The Netherlands
Peter Laverman
- Department of Nuclear Medicine, Radboud University Nijmegen Medical Center, Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
- Corresponding author. Tel.: +31 24 3615054; fax: +31 24 3618942.
J. Han J.M. van Krieken
- Department of Pathology, Radboud University Nijmegen Medical Center, Nijmegen, 6500 HB Nijmegen, The Netherlands
Wim J.G. Oyen
- Department of Nuclear Medicine, Radboud University Nijmegen Medical Center, Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
Fokko M. Nagengast
- Department of Gastroenterology, Radboud University Nijmegen Medical Center, Nijmegen, 6500 HB Nijmegen, The Netherlands
Joost P.H. Drenth
- Department of Gastroenterology, Radboud University Nijmegen Medical Center, Nijmegen, 6500 HB Nijmegen, The Netherlands

Received 30 September 2005; received in revised form 27 October 2005; accepted 23 November 2005.

Abstract

Background

Azoxymethane (AOM) is a potent carcinogen that induces colorectal cancer and adenomas in rats. [¹⁸F]FDG-PET is a molecular imaging technique that is based on the elevated uptake and retention of radiolabeled glucose. At present, it is unknown at which stage FDG accumulation occurs during the adenoma carcinoma sequence. To address this issue, we studied the FDG uptake in AOM-induced rat colorectal adenocarcinoma (CRC) and correlated this with histopathological findings.

Methods

Seventy Fischer 344 rats were injected with AOM. Terminal autopsy took place 20–38 weeks after the first AOM injection. After [¹⁸F]FDG PET scanning, the rats were sacrificed, tissue [¹⁸F]FDG uptake was measured, followed by histopathological examination.

Results

Macroscopic examination revealed 21 tumors (7 located in the small bowel and 14 in the colon) in 19 rats. On histological examination, we found 10 colonic adenocarcinomas (the first being observed at Week 22) and 7 adenocarcinoma in the small bowel. In total, seven colon adenomas were found in five rats, six of which expressed high-grade dysplasia. The [¹⁸F]FDG accumulation in small intestine carcinomas was well beyond background accumulation (P<.0001). On PET scanning, two rats showed focal accumulation of the abdominal area, corresponding to small intestine carcinomas.

Conclusion

Adenocarcinomas had a significantly higher [¹⁸F]FDG uptake than background bowel uptake. [¹⁸F]FDG uptake was lower in adenomas than in carcinomas. These data suggest that the AOM model allows the evaluation of intervention strategies with [¹⁸F]FDG uptake as a valid outcome measure.

Keywords: Azoxymethane, Colonic adenomas, [¹⁸F]FDG-PET, Rats