[Anti-CEA immunoscintigraphy in postoperative follow-up of tumor patients. Differentiated use of various monoclonal antibody preparations].

The sensitivity of immunoscintigraphy (ISC) with monoclonal antibodies (Mab) depends on the Mab type, the radiophysical properties of the isotope, the labeling method and the tumor localization. We investigated 38 studies with three different Anti-CEA Mab (In111/I131 BW 431, n = 12; I131 IMACIS-1, n = 11; Tc99m BW 431/26, n = 15) in 35 postoperative tumor patients (31 colorectal, 1 gastric, 2 breast and 1 pancreas cancer) with a total of 62 tumor manifestations. Planar ISC was used in all studies. A dual isotope technique with Tc99m-colloid was applied for imaging of liver metastases in the In111/I131 BW 431/31 and I131 IMACIS-1 studies. Whereas the global sensitivity, ranging from 64-73%, was comparable, the different physiological properties of the Mab preparations caused marked differences in the imaging capabilities of certain tumor localizations, especially in the liver. All Mab underestimated the extent of liver involvement, however, the highest regional sensitivity (75%) was found with the I131 IMACIS-1. In contrast, Mab with the highest physiological liver uptake (In111 BW 431/31, Tc99m BW 431/26) imaged liver metastases in most cases unspecifically as cold spot, yielding a sensitivity of 0-9%. No differences between the Mab were seen in the regional sensitivity with respect to lung metastases, which ranged between 33-40%. All tested Mab showed a high sensitivity in imaging local recurrences ranging between 50% for the I131 IMACIS-1 and 100% for the Tc99m BW 431/26. We conclude, that in postoperative tumor patients anti-CEA ISC with Tc99m BW 431/26 is the method of choice for the detection of local recurrences.(ABSTRACT TRUNCATED AT 250 WORDS)