The diagnostic efficacy of whole body 18F-FDG PET CT in detection of unexpected second primary malignancy in cancer patients

Abstract

Purposeto assess the efficacy of FDG PET/CT in detecting unexpected additional primary malignant neoplasms in patients being evaluated by PET/CT for known malignancies compared to conventional staging work-up (CSW). Patients and methodsOf 1889 patients referred for whole-body FDG PET/CT in the period from February 2015 to May 2016, only 273 were included in this prospective study. Patients included are those with histopathologicaly proven primary malignancy and sent for initial tumor staging before treatment within 1month of CSW that was performed for the patients according to the site and cell type of the primary tumor. Histopathologic examination was performed for lesions indicating additional primary cancer detected by either PET/CT or CSW. ResultsIn 13 out of 273 patients included in the study (4.76%) only were proved to have additional primary cancer, the PPV of PET/CT for detecting an additional primary cancer was 56.5%. Also, it showed high sensitivity of 89.2%, which was significantly higher than 23% from the CSW (P<0.005). ConclusionPET/CT is more accurate than CSW for detecting additional primary cancer with a higher sensitivity and positive predictive value, which consequently affect further management.