Anticarcinoembryonic antigen immunoscintigraphy with a 99mTc-Fab' fragment (Immu 4) in primary and recurrent colorectal cancer. A prospective study.

Forty-seven patients were submitted to 68 radioimmunoscintigraphic investigations for primary or recurrent colorectal cancer. Immunoscintigraphy with Immu-4 correctly detected 28 primary colorectal cancers of 29 and 12 of 12 recurrent colorectal cancers. Overall accuracy was 93.75 percent in primary and 91.6 percent in recurrent colorectal cancer. Immunoscintigraphy had a decisive influence on treatment planning in every third primary colorectal cancer patient and was by far superior to CT scan in the detection of early recurrences, especially in patients with a history of abdominoperineal or low anterior resection. Immu-4 scintigraphy is a safe and convenient diagnostic approach to colorectal cancer. Because radioactivity is acceptably low and the method is absolutely free of side effects, there are no objections to the repeated use of immunoscintigraphy which provides important information in primary diagnosis as well as in the follow-up of colorectal cancer patients.