Purpose: The role of 18F-FDG PET has been studied in ovarian carcinoma, but its sensitivity and specificity calculations are based on dedicated PET acquisition, not PET/CT in the majority of the published studies. Therefore, we were prompted to review our experience with PET/CT in the management of patients with ovarian carcinoma.
Materials and methods: This is a retrospective study of 43 women with ovarian carcinoma, 27-80 years old (average: 53.9±7.8), who had whole-body PET/CT at our institution from 1 January 2003 to 31 August 2006. We reviewed the patients' outcomes from medical records and compared them to the interpretation of the PET/CT scans. Sensitivity and specificity were calculated using a 2×2 table with pathology results (79.1% of the patients) or clinical follow-up (20.9% of the cases) as the 'gold standard'. Confidence interval (CI) estimations were performed using the Wilson score method.
Results: All patients had advanced stage ovarian cancer and the study was requested for re-staging. A total of 60 scans were performed: 30 patients had one scan, nine patients had two scans and four patients had three scans. The administered doses of 18F-FDG ranged from 381.1 to 769.6 MBq (average: 569.8±73.3). PET/CT had a sensitivity of 88.4% (95% CI: 75.1-95.4) and a specificity of 88.2% (95% CI: 64.4-97.9) for detection of ovarian cancer. The SUV max of the detected lesions ranged from 3 to 27 (average: 9.4±5.9). The CA-125 tumor marker ranged from 3 to 935 kU/ml (average: 265.2) in patients with positive scans and 4-139 kU/ml (average: 17.1) in patients with negative scans. This difference was statistically significant (P value: 0.0242).
Conclusion: This study confirms the good results of 18F-FDG PET/CT for identification of residual/recurrent ovarian cancer, as well as for distant metastases localization. PET/CT should be an integral part in evaluation of patients with high-risk ovarian cancer or rising values of tumor markers (CA-125), prior to selection of the most appropriate therapy.