Positron emission tomography for the evaluation of patients with colorectal cancer

Approximately 40% of patients treated with curative intent for colorectal carcinoma eventually recur. In about one third of these patients, the lesion is localized and potentially resectable. Typically, the recurrence is characterized by findings on diagnostic imaging studies and may be accompanied by a rise in the serum carcinoembryonic antigen (CEA) levels. In a few patients, however, the asymptomatic rise in CEA is not accompanied by diagnostic findings on computed tomography (CT). We report a case herein, of a patient with rising CEA, noted 1 year after completion of adjuvant chemotherapy for node-positive colorectal cancer. CT and laparoscopic exploration were nondiagnostic. In order to further evaluate the rise in CEA, positron emission tomography (PET) was performed. PET revealed an area of increased uptake in the right lobe of the liver. Resection of the metastatic liver lesion resulted in a subsequent drop in the CEA levels.