Value of ¹⁸F-FDG PET/CT in the diagnosis of multiple primary malignant neoplasms

Objective To explore the value of ¹⁸F-FDG PET/CT in diagnosis of multiple primary malignant neoplasms.

Methods Five thousand eight hundred and twenty-two patients with suspected tumors were retrospectively reviewed. All cases underwent ¹⁸F-FDG PET/CT and 32 patients were confirmed with multiple primary malignancies by biopsy or resection. Mean standardized uptake value(SUV_mean) was calculated and SUV_mean≥2.5 and abnormal morphological changes on CT were used as a standard to diagnose a malignant tumor. The sensitivity and accuracy of PET/CT in diagnosis of multiple primary maligant neoplasms were calculated.

Results The incidence rate of multiple primary malignant neoplasms was 0.55%. Double primary malignant neoplasms were in 30 cases and triplicate primary malignant tumors were in 2 cases. There were 66 malignant tumor lesions. The average of SUV_mean in 66 malignant tumor lesions was 6.68±3.61. The results of PET/CT were 58 true positive lesions and 8 false negative lesions. The sensitivity and accuracy of ¹⁸F-FDG PET/CT in diagnosis of multiple primary malignant neoplasms were 87.9% and 87.9% respectively.

Conclusion ¹⁸F-FDG PET/CT whole body scan has an important value in the diagnosis of multiple primary malignant neoplasms.