Radioimmunoscintigraphy of colorectal carcinomas with 99mTc-labelled antibodies.

Background/aims: The aim of the study was the evaluation of the clinical validity of immunoscintigraphy with 99mTc labeled antibodies for the detection of metastases and recurrences of colorectal carcinomas.
Methodology: We examined 17 patients with colorectal carcinomas. Scintigraphy was performed with anti-CEA MoAb 99mTc-BW 431/26.
Results: Recurrences of carcinomas were detected and confirmed by surgery in 6 patients, recurrences with liver metastasis in 5 patients, and only liver metastases in 3 patients. Planar immunoscintigraphy was positive in 5/8 patients with liver metastases and 8/11 patients with recurrences, whereas in 1/8 liver metastases and 3/11 recurrences were detected only by tomography. In two patients with metastases in the abdominal lymph nodes immunoscintigraphic findings both on planar scintigraphy and tomoscintigraphy were false negative.
Conclusions: Immunoscintigraphy with 99mTc labeled antibodies can be useful in the diagnosis of recurrences and metastases of colorectal carcinoma, viability assessment after radiotherapy and in the choice of the adequate surgical treatment.