Value of 18F-FDG PET-CT in surveillance of postoperative colorectal cancer patients with various carcinoembryonic antigen concentrations

AIM:To evaluate the value of positron emission tomography(PET)/computerized tomography(CT)in surveillance of colorectal cancer(CRC)patients with different carcinoembryonic antigen(CEA)concentrations.METHODS:One hundred and six postoperative CRC patients who had suspected recurrence or metastasis and received fluorodeoxyglucose(FDG)PET/CT within one week were included in this study.The final diagnosis was confirmed by histological examination or clinicalfollow-up over at least six months.RESULTS:The sensitivity,specificity,and accuracy of FDG PET/CT were 95.2%,82.6%,and 92.5%,and94.8%,81.4%and 92.8%,respectively,in the caseand lesion-based analyses.The sensitivity and accuracy of FDG PET/CT significantly differed from CT in both analyses(χ2=8.186,P=0.004;χ2=6.201,P=0.013;χ2=13.445,P=0.000;χ2=11.194,P=0.001).In the lesion-based analysis,the sensitivity,specificity,and accuracy of FDG PET/CT in the abnormal CEA group were97.8%,82.6%,and 95.6%,compared with 81.3%,80%,and 80.6%for patients with normal CEA levels.In case-based analysis,the sensitivity,specificity,and accuracy of FDG PET/CT were 97.2%,77.8%,and 95%in abnormal CEA group.Only in lesion-based analysis,the sensitivity and accuracy of FDG PET/CT in the abnormal CEA group were significantly superior to those in the normal CEA group(χ2=6.432,P=0.011;χ2=7.837,P=0.005).FDG PET/CT changed the management in 45.8%of patients with positive scans.CONCLUSION:FDG PET/CT showed superior diagnostic value and is an advisable option in surveillance of postoperative CRC patients with a vague diagnosis.