Clinical use of combined positron emission tomography and computed tomography (FDG-PET/CT) in recurrent ovarian cancer.

Objective: The aim of this study was to evaluate the use of co-registered PET/CT using F-18 fluorodeoxyglucose (FDG) for surveillance and follow-up of ovarian cancer patients to detect recurrent disease.

Material And Methods: A retrospective chart review was performed on 39 ovarian cancer patients who underwent a total of 59 FDG-PET/CT scans. The following information was obtained: clinical indication for FDG-PET/CT, the results of FDG-PET/CT particularly with regard to the additional diagnostic information, the localization of disease and subsequent clinical patient management.

Results: Twenty-four FDG-PET/CT were performed in 22 patients with previously negative or indeterminate CT scans but rising CA-125 levels providing a sensitivity of 90% for localizing disease. Nine FDG-PET/CT in 8 patients with clinical symptoms of recurrence but normal CA-125 levels detected all three patients who had recurrent disease confirmed within 6 months of follow-up. In addition, 4 FDG-PET/CT performed as routine follow-up with no clinical evidence of recurrent disease were true-negative in all cases. Fourteen FDG-PET/CT in 12 patients with recurrent disease already identified by conventional CT imaging were useful in guiding treatment decisions such as radiation therapy, surgery or chemotherapy by confirming the recurrence and more precisely localizing the site(s) of disease. Of note, FDG-PET/CT helped to avoid surgery in four patients who had additional disease detected in unresectable anatomic areas. A total of 51 FDG-PET/CT were performed in the patients described above with an overall sensitivity and specificity of 94.5% and 100%, respectively. Eight FDG-PET/CT scans in five patients performed for assessment of treatment response following chemotherapy or radiation were useful as the disease was not clearly visualized by conventional CT imaging at baseline.

Conclusions: In our experience, FDG-PET/CT has the greatest utility in settings of suspected ovarian cancer recurrence, particularly in patients with rising CA-125 levels and negative conventional imaging. FDG-PET/CT was specifically helpful in optimizing the selection of patients for site-specific treatment, including radiation treatment planning, and aided in the selection of optimal surgical candidates. The co-registered metabolic-anatomic information from combined FDG-PET/CT holds promise in replacing the single imaging procedures.