Association between carcinoembryonic antigen levels and the applied value of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography in post-operative recurrent and metastatic colorectal cancer.

Positron emission tomography (PET) using ¹⁸ F-fluorodeoxyglucose has been widely used for analyzing cellular metabolism. The present study aimed to evaluate the association between the diagnostic value of PET/computed tomography (CT) in patients with post-operative recurrent and metastatic colorectal cancer (CRC), and the different levels of carcinoembryonic antigen (CEA). A total of 105 suspected recurrent and metastatic CRC patients (67 males and 38 females; mean age, 48.5 years) were included in this retrospective study. All the patients underwent PET/CT examination. The differences in the PET/CT diagnostic values of CEA-positive and -negative patients with recurrent CRC following surgery were retrospectively analyzed and compared. Among the 105 CRC patients, 87 exhibited recurrence and metastasis, as confirmed by histopathological diagnosis or clinical follow-up data. By contrast, the PET/CT examination results revealed that 85 cases were true positives (a false positive foci was diagnosed in one of the patients), 18 were true negatives and 2 were false negatives. Correspondingly, the sensitivity and degree of accuracy were 97.7 and 97.1%, respectively. The detection rates of PET/CT for the recurrence and metastases were 85.3% in the CEA-positive group and 75.7% in the CEA-negative group. No significant differences were observed between the two groups. Overall, CEA levels do not help improve the detection rate of PET/CT in the recurrence and metastasis of CRC. PET/CT imaging has a high sensitivity and degree of accuracy in detecting recurrence and metastasis following CRC surgery. Therefore, this method is ideal for monitoring relapsed and metastatic foci of post-operative colon cancer cases.