[Immunoscintigraphy with monoclonal antibody Tc99m BW 431/26 in the diagnosis of colorectal carcinoma]. / Inmunogammagrafía con el anticuerpo monoclonal 99mTc BW 431/26 en el diagnóstico del carcinoma colorrectal.

ABSTRACT

BACKGROUND: The use of monoclonal antibodies against tumoral antigens marked with radioactive isotopes is the basis of immunoscintigraphy. The specificity of the technique is high owing to its intrinsic characteristics. METHODS: 40 patients with colorectal cancer who were awaiting surgery were evaluated by immunoscintigraphy. The group consisted of 34 primary diseases and 7 recurrences. Two days before surgery the specific monoclonal antibody BW 431/26 (Behringwerke, FRG) labeled with 99mTc was injected and scintigraphic images were obtained 4 and 24 hours after its administration. RESULTS: The following results were found after a comparison of the data with those from other diagnostic procedures and surgical findings: in primary disease, sensitivity (S) was 59% and accuracy (A) was 56% (these rates increased to 82% and 75%, respectively, when rectal tumors were excluded). For hepatic metastases, S was 44% and A was 85%. In the recurrence group the results were 4 true positives, 2 false negatives (in the rectum), and one false positive. CONCLUSIONS: These results confirm the validity of immunoscintigraphy in patients with colorectal carcinoma. This test may supplement the information of other diagnostic tests, particularly when these have more limitations as it is the case for recurrences.