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- • Ultrasound of the abdomen and, if indicated, within the rectum. Endorectal ultrasonography can accurately
- show tumor invasion and enlarged lymph nodes outside the rectum, but cannot indicate if enlarged lymph
- nodes actually contain metastatic tumor.
- • Abdominal CT and MRI scans to identify distant metastases before surgery.
- • Chest x-ray may reveal lung metastases.
- • PET (positron emission tomography) scanning, if available (experimental) can help assess the early response
- of liver metastases to chemotherapy by showing changes in sugar metabolism.
- • Radioimaging body scan before surgery with CYT-103 monoclonal radiolabeled indium antibodies may help
- detect hidden metastatic disease in about 12 percent of cases. This experimental method can complement CT
- scans, increasing their diagnostic sensitivity for finding hidden metastatic sites in the pelvis and other areas
- outside the liver. Other monoclonal antibody and imaging tests are being developed. Current monoclonal
- antibody scans are not completely reliable in the detection of liver metastases.
- Studies with anti-CEA monoclonal antibodies have shown a high accuracy in detecting tumors smaller than
- 1/2 in. (1 cm). This may be helpful to the surgeon. The usefulness of these radioisotope scans is not yet
- certain.
-
- Endoscopy and Biopsy
- • Examination of the entire colon with a colonoscope (colonoscopy), or the lower part of the colon and rectum
- with a flexible tube (proctosigmoidoscopy) and biopsy of any mass found.
-