18F-FDG PET/CT is superior to contrast enhanced CT in evaluation of response to treatment in patients with recurrent ovarian cancer

348 Objectives To evaluate the role of 18F-Flurodeoxyglucose positron emission tomography/computed tomography compared to contrast enhanced computed tomography in assessment of response to second-line treatment in patients with recurrent ovarian cancer. Methods The study prospectively enrolled 32 patients with documented ovarian recurrence. Each patient had a baseline concurrent PET/CT and Ce-CT for status evaluation. Then they received their scheduled therapies and re-assessed using a second concurrent PET/CT and Ce-CT studies. Studies were interpretated according to EORTC and RECIST criteria for PET/CT and Ce-CT respectively. The results were finally reported as either negative for residual disease when there is complete response (CR) or as positive for residual disease when there was progressive disease (PD), stable disease (SD) or even regressive disease (RD). The final diagnosis was reached upon subsequent follow-up by PET/CT or histopathology. Results 24 patients remained positive for residual disease leaving only 8 patients with no evidence of disease (CR) in final follow up. PET/CT successfully ruled out disease in (7/8) patients resulting in specificity 88%, while Ce-CT excluded disease only in (2/8) patients resulting in specificity of 25%. PET/CT correctly categorized patients as complete responders (TN) in 5/6 patients with FP non-responders in Ce-CT yielding statistically significant disagreement between two modalities (P= 0.03). Overall, PET/CT was statistically more accurate (P=0.0001). Moreover Ce-CT categorization of disease response was not associated with the final follow up results (P 0.15), while PET/CT showed significant association (P Conclusions 18F-FDG PET/CT is superior to Ce-CT in assessment of response to treatment in patients with recurrent ovarian cancer.