Positron Emission Tomography (PET)- Computed Tomography (CT) for Preoperative Staging of Colorectal Cancers

Purpose: The purpose of this study is to evaluate the usefulness of positron emission tomography (PET)- computed tomography (CT) for preoperative tumor staging in cases of colorectal cancer. Methods: Between July 2006 and September 2007, seventy-six patients with a diagnosis of colorectal cancer (43 males and 33 females; mean age: 60.4±10.13 years; range: 34∼82 years) selected prospectively were studied for staging by using Chest X-ray, abdominal CT and PET-CT. Results: The sensitivities and the specificities for N-staging were 76.9% and 35.1% for CT, 61.8% and 66.7% for PET-CT, and both procedures showed a relatively low diagnostic accuracy (CT 57.9%, PET-CT 61.8%). In the PET-CT alone, six distant metastatic lesions and four multiple primary malignancies were found. The locations of the distant metastases were the liver, the axillary node, the common iliac node, the subclavicular node, the peritoneum, and the lung. The locations of the multiple primary maligancies in extracolonic sites were 3 in the thyroid and 1 in the nasopharynx. Conclusions: For N-staging, preoperative PET-CT is no more useful than CT, but PET-CT is required before surgery to find lesions that cannot be found with conventional studies.