Role of 18F FDG PET/CT in evaluation of post-operative ovarian carcinoma

Abstract

BackgroundWe evaluated the sensitivity, specificity and accuracy of fluorine-18-fluorodeoxyglucose with positron emission tomography/computed tomography (18F-FDG-PET/CT) in a group of patients with suspicion of ovarian cancer recurrence. It is considered a diagnostic dilemma, particularly in the 2 years following first-line therapy. CA125 serum levels computed tomography (CT) and other modalities are used during routine follow-up. These traditional modalities could provide a significant number of false-negative or equivocal results even in the presence of elevated CA125 levels. So the performance of 18F-FDG-PET/CT is essential for the optimal diagnosis of recurrence and treatment planning.ResultsStudying PET/CT behaviour in the detection of ovarian cancer recurrence, 18F-FDG-PET/CT had an accuracy of 98% with sensitivity and specificity of 98% and 100%, respectively. 18F-FDG-PET/CT had a PPV of 100% and NPV of 83%. While studying the CA125 level (> 35 U/ml) to detect the ovarian cancer recurrence during patient follow-up, the CA125 level had an accuracy of 50% with a sensitivity ratio and specificity ratio of 47% and 80%, respectively. CA-125 level had a PPV of 95% and NPV of 14%. In comparison between conventional CT and PET/CT studies, the PET/CT diagnosed local tumor recurrence in 16 patients (32%), while CT scan diagnosed local tumor recurrence in only 3 patients (6%), and PET/CT detected peritoneal recurrence in 34 patients (68%). CT scan found peritoneal deposits in 11 patients (22%), also the PET/CT showed suspicious abdominal LNS in 22 patients (44%) while, CT scan showed suspicious abdominal LNS in 4 patients (8%), and PET/CT showed suspicious pelvic LNS in 16 patients (32%). CT scan showed suspicious pelvic LNS in 7 patients (14%). PET/CT detected distant organ metastases in 18 patients (36%). CT scan detected distant organ metastasis in only 8 patients (16%). Comparison between CT and PET/CT in 32 follow-up cases for the detection of local tumor recurrence, peritoneal deposits, suspicious abdominal/pelvic LNs and distant organ metastasis. There was a statistically significant difference between CT and PET/CT the end results (p < 0.0001, p = 0.0047, p = 0.001, p = 0.03).Conclusions18F-FDG-PET/CT is more sensitive in detection and localization of ovarian cancer recurrence and more superior than the other imaging modalities.