Evaluating the efficacy of a new imaging test in detecting recurrence or metastases in patients with colorectal cancer

Monoclonal immunoscintigraphy (MI) is a procedure used to find cancer cells in the body. This test is done by injecting the patient with a radioactive antibody (a protein that emits radiation) which binds to cancer cells. Then a picture is taken of the whole body to see where the antibody was localized, thus localizing the cancer. In patients with colorectal cancer (CRC), there are several blood markers such as CA 19-9 (carbohydrate antigen 19-9) or CEA (carcinoembryonic antigen) that predict the presence of cancer. However, not all these patients have symptoms, thus imaging tests should be undertaken in order to confirm the presence of CRC. This study evaluated the efficacy of MI in detecting recurrence or metastases in patients treated for CRC.

This study included 53 patients who have been previously treated for CRC. All patients had high levels of CEA or CA 19-9 and were suspected of recurrent disease or metastases. All patients underwent MI to test if the cancer has come back or has spread. In addition, patients also underwent other imaging tests such as ultrasonography, contrast radiography, colonoscopy, computer tomography or magnetic resonance imaging. Using these complementary imaging techniques allowed a comparison to be performed to show if MI was a better diagnostic technique.

Results show that MI was better in detecting metastases from CRC compared to other imaging tests. Out of the 53 patients who took part, MI detected a recurrence in 38 patients. The other imaging tests confirmed this in 35 patients. MI showed no recurrence in 15 patients, which was confirmed in 14 patients by other imaging tests. The levels of the cancer marker CEA were higher in patients who had a detected recurrence.

In conclusion, monoclonal immunoscintigraphy was highly specific in detecting metastases or recurrence in patients with colorectal cancer. 

This study included a very small sample of patients. Future studies should consider larger populations of patients to confirm the results of this research.