Incremental benefits of FDG positron emission tomography over CT alone for the preoperative staging of ovarian cancer

OBJECTIVE. The purpose of this study was to determine whether the addition of positron emission tomography (PET) with the radiotracer FDG to cross-sectional imaging, such as CT, increases accuracy in the detection of tumor spread. SUBJECTS AND METHODS. Fifteen patients who were thought to have ovarian cancer on the basis of the results of physical examination, sonography findings, and level of serum cancer antigen 125 were enrolled over an 11-month period. After screening, patients underwent two imaging examinations-abdominopelvic CT and whole-body FDG PET-within 2 weeks before surgery. Also before surgery, staging accuracy was assessed separately using CT with or without FDG PET (which was based on modifications of the International Federation of Gynecology and Obstetrics [FIGO] criteria). The results of the histology and surgery findings were used to assess the accuracy of the scanning findings. RESULTS. Staging revealed stage III disease in seven patients (IIIC, n 6; IIIB, n = 1), stage II in three (IIC, n = 2; IIIB, n = 1), and stage I in five (IC, n = 3; IA, n 2), according to the FIGO criteria. Although CT staging correlated with postoperative staging in eight (53%) of 15 patients, consensus evaluation of CT with FDG PET staging improved correlation with postoperative staging in 13 (87%) of 15 patients. CONCLUSION. The addition of FDG PET to CT increases accuracy in staging of ovarian cancer.