Radioimmunoscintigraphy with 99mTc-labelled anti-CEA monoclonal antibodies in colorectal carcinoma patients

Sixteen patients (2 female and 14 male, aged 42-75) were given intravenous injections with 99mTc (555-740 MBq)-labelled anti-CEA MAb (CEA-Scan, Mallinckrodt Medical and M-CEATEC, Sorin Biomedica). Five of them were with duly established or established or suspected primary colorectal carcinoma, and eleven were studied postoperatively after recording an increase CEA levels in serum. The patients were scanned within 4-24 h of infusion using planar and tomographic imaging in rotation gamma-camera DIACAM (Siemens). At all 16 patients 27 true positive results were obtained: in 7 primary colorectal carcinomas, 5 locally recurrent tumors, 7 liver metastases, 6 lymphogeneous lesions and two - in the ureteral region. True negative results were established at three patients, false positive - in one patient with chronic inflammation, and false negative results - in 3 cases with liver metastases foci < 8 mm. Having 90 % sensitivity, 75 % specificity and 82.3 % accuracy, radioimmunoscintigraphy is a highly informative and sensitive imaging method for diagnosing and following up of primary, recurrent and metastatic foci in colorectal carcinoma patients. (author)