Objective: To assess the utility of nuclear imaging with labelled monoclonal antibody against CEA immu-4 Fab' (CEA-scan) and the computed tomography (CT) in the follow-up of colorectal cancer after therapy and his accuracy in the detection of recurrent disease.
Materials and methods: 48 studies underwent to 45 patients (25 men and 20 women) with an average age of 64, diagnosed and treated of colorectal cancer, 5 hours after the intravenous administration of 1.25 mg of arcitumomab (CEA-scan) labelled with 945 MBq of 99mTc. The reasons to request the CEA-scan were signs compatible with active disease in 15 cases, post-therapy control in asyntomatic patients in 17 and suspicious of recurrence in 16. Histological confirmation of the lesions was obtained in 12 patients and the rest was assessed by an average of evolution time of 26 months, CT and blood CEA levels.
Results: The values of sensitivity, specificity, PPV and NPV obtained for the CEA- scan were of 91%, 76%, 77% y 90% respectively; 78%, 80%, 78% y 80% respectively for the CT and 65%, 42%, 88% y 74% respectively for the blood CEA levels. The CEA-scan and blood CEA levels combination showed the best results 100%, 95%, 93% y 100% respectively.
Conclusion: We did not find any correlation between blood CEA levels and CEA-scan results. The CEA-scan showed the highest sensitivity an NPV. The combination of different techniques showed better results than an individual valoration.