The clinical significance of 18F-FDG-PET/CT in early detection of second primary malignancy in cancer patients

Abstract

This retrospective study evaluated the diagnostic value of integrated whole-body (18)F-fluorodeoxyglucose positron-emission tomography and computed tomography ((18)F-FDG-PET/CT) in early detection of second primary malignancies in cancer patients. From June 2007 to October 2008, 677 cancer patients who had undergone a whole-body (18)F-FDG-PET/CT imaging for the purpose of initial tumor work-up were included in this study. We retrospectively analyzed the follow-up results of patients with newly detected lesions presented on the (18)F-FDG-PET/CT images, which had not been previously detected by other modalities. We diagnosed suspected second primary malignancies by considering PET/CT images and clinical information as well. With the pathological results as the golden standard and complementary clinical follow-up investigations, the sensitivity and the positive-predictive value (PPV) of diagnosis of a second primary malignancy were calculated. We retrospectively analyzed the follow-up results of 338 patients with newly detected lesions. Twenty-one patients were finally diagnosed with second primary malignancies. In addition, the second primary malignancies of 17 patients were diagnosed at an early stage (P = 0.007). Thirteen patients were without any related symptoms which are indicative of second primary malignancies (P = 0.38). The median Karnofsky performance status scale of these patients in the last follow-up study was 80 points. The sensitivity of (18)F-FDG-PET/CT in detecting a second primary malignancy was 95.24%, the PPV was 74.07%, which was much higher than the PPV of diagnosing with no clinical information. (18)F-FDG-PET/CT is a useful tool in detecting second primary malignancies in an early stage and can improve the therapeutic effects experienced by the patients.