Positron emission tomography with 18F-fluoro-2-deoxyglucose for the detection of recurrent ovarian cancer

Abstract
Recurrent ovarian cancer is refractory and resistant to treatment in most patients, and no effective treatment for it has been established. Starting a treatment when tumors still consist of micro foci may contribute to improvement of prognosis. Therefore, the early diagnosis of relapse is important.Among patients with epithelial ovarian cancer in whom initial treatment achieved remission between April 1998 and December 2003, those patients in whom the cancer-related antigen (CA)125 level was increased during the subsequent follow-up period, or those who showed abnormal computed tomography (CT)/magnetic resonance imaging (MRI) findings despite normal CA125 levels, were examined by 18F-fluoro-2-deoxyglucose - positron emission tomography (FDG-PET). We compared the rates of accurate diagnosis of recurrence achieved using CT/MRI, CA125, and FDG-PET in patients with a definitive diagnosis of relapse.We investigated 29 patients with epithelial ovarian cancer. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of FDG-PET were 84.6% (22/26), 100% (3/3), 100% (22/22), 42.9% (3/7), and 86.2% (25/29), respectively. These values were higher than the corresponding values obtained using CT/MRI or CA125 levels.FDG-PET may be very useful for identifying sites of recurrent ovarian cancer, although this procedure had a low NPV because of the high rate of false-negative findings for micro or cystic lesions.