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Colorectal Cancer
Image:
62 year old woman with history of rectal cancer and rising CEA. PET study demonstrates large focus of FDG activity in rectal bed indicating recurrence as well as a site of metastatic spread to pre-sacral space.
Colorectal Cancer - Case Study #2
Study Background:
A 61yr old male with recently diagnosed colon cancer was studied as part of an initial staging examination prior to adjuvant therapy. The PET study was performed 3 weeks after primary tumor resection. CT imaging of the liver revealed multiple mass defects suspicious for metastatic disease.
PET Imaging:
Fifty minutes after the injection of 692 MBq of 18F-FDG, images of the neck, chest, abdomen, and pelvis were obtained with a GE Advance tomograph (7 minutes emission, 3 minutes transmission data per bed position). Data were reconstructed using an OSEM algorithm and segmented attenuation correction. The PET study demonstrates two areas of increased FDG uptake in the liver that correspond to the findings on CT. In addition, there is an area of markedly increased FDG uptake in the right anterior mediastinum suspicious for metastatic spread, not noted on CT. Finally, there is increased metabolism in the area of the surgical anastamosis as well as the abdominal wall suture site which most likely represent post-surgical changes.
Discussion:
PET imaging has become a valuable diagnostic tool in the initial staging and treatment planning of colorectal cancer. When used in concert with conventional imaging such as CT, PET has been shown to impact clinical management decisions in 29-40% of all cases through its ability to upstage or downstage cancer. The superior sensitivity of PET oftentimes leads to the identification of unsuspected extra-hepatic metastases thereby eliminating needless surgeries and curative therapy regimens.
Reference:
Ruers TJ, Langenhoff BS, et al. Value of positron emission tomography with [F-18]fluorodeoxyglucose in patients with colorectal liver metastases: a prospective study. J Clin Oncol 2000 Jan 15:20(2):388-95.
Meta J, Seltzer M, et al. Impact of 18F-FDG PET on managing patients with colorectal cancer: the referring physician’s perspective. J Nucl Med 2001 Apr;42(4):586-90
Images courtesy of:
Akron General Hospital
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