The value of PET/CT imaging for detecting primary malignant tumor to patients with elevated serum CA19-9 / 中国医师杂志

ABSTRACT

Objective To investigate the diagnostic accuracy of malignant tumor of 18F-fluorodeoxyglucose positron emission tomography/computed tomograprhy (18F-FDG PET/CT) imaging in the patients of elevated serum carbohydrate antigen 19-9 (CA19-9) and its correlation with maximum standardized uptake value (SUVmax) and serum CA19-9 level.Methods Whole-body 18F-FDG PET/CT scan was performed in 149 patients with elevated serum CA19-9 level without the history of malignancy.Blood sample was drawn in each case for CA19-9 assay two weeks or less before the performing PET/CT.Final diagnoses were confirmed by operation/biopsy pathological results and clinical follow-ups.Results Among the 149 patients,64 cases were finally diagnosed as malignancies and 85 cases of non-malignancy diseases.The true positive of the diagnoses by 18F-FDG PET/CT was 60 cases,the false positive 13 cases,the true negative 72 cases,the false negative 4 cases.The accuracy of diagnosis of malignant tumor with elevated serum CA19-9 was 43.0％,while elevated serum CA19-9 combined with 18F-FDG PET/CT imaging was 88.6％,with statistically significant difference (x2 =59.882,P ＜ 0.05).The serum CA19-9 was divided into 4 groups according to the different levels of 37-100 U/ml,100-500 U/ml,500-1000 U/ml and ＞ 1 000 U/ml.The diagnostic accuracy of each group of PET/CT was 94.5％,84.9％,81.3％ and 88.0％,respectively.There was no statistically significant difference between each group (x2 =3.503,P ＞ 0.05).The area under the curve (AUC) of the serum CA19-9 for the diagnosis of malignant tumor (ROC) was 0.726,and the sensitivity and specificity of the diagnostic boundary value of 152.75 U/ml were 70.3％ and 68.2％,respectively.The AUC of SUVmax in diagnosis of malignant tumor was 0.742,the best cutoff value was 6.95,and the sensitivity and specificity were 73.3％,69.2％ respectively.Conclusions 18 F-FDG PET/CT is useful for detecting malignant tumors combined with serum tumor marker CA19-9.The patients with elevated serum CA19-9 are necessary to do PET/CT imaging,especially serum CA19-9 ＞ 152.75 U/ml.And it should be considered malignant tumor when SUVmax ＞ 6.95.