Objective   This work aimed to evaluate the relationship of the diagnostic value of PET/CT in patients with postoperative recurrent and metastatic colorectal cancer (CRC), as well as with different levels of carcino-embryonic antigen (CEA), during PET/ CT scanning.

  Methods  Data of 75 patients (46 males and 29 females) with suspected recurrent and metastatic CRC were collected.The patients underwent PET/CT examination in Shanxi Provincial Tumor Hospital in Taiyuan.The differences of the PET/CT diagnostic values in CEA-positive and CEA-negative patients with recurrent CRC after surgery were retrospectively analyzed and compared.

  Results  Among the 75 CRC patients, 67 had recurrence and metastasis as confirmed by histopathological diagnosis or clinical follow-up data.By contrast, PET/CT examination results revealed 65 cases were true positive (a false positive foci was diagnosed in one of the patients), 8 were true negative, and 2 were false negative.Correspondingly, the sensitivity and degree of accuracy were 97.0% and 96.0%, respectively.The detection rates of PET/CT for the recurrence and metastases were 89.3% in the CEA-positive group and 82.1% in the CEA-negative group.No significant differences were observed between the two groups.

  Conclusion  CEA levels do not help improve the detection rate of PET/CT in the recurrence and metastasis of CRC.PET/CT imaging has high sensitivity and degree of accuracy in detecting recurrence and metastasis after colon cancer surgery.Therefore, this method is ideal for monitoring relapsed and metastatic foci of postoperative colon cancer cases.