We evaluated the clinical role of the combination of positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) and tumor marker CA125, in the detection of recurrence after initial therapy for epithelial ovarian cancer. The indication is the cases that cannot be confirmed the recurrence by conventional imaging modalities. Ninety patients underwent PET and computed tomography, including the measurement of specific tumor markers. FDG-PET confirmed recurrence in 46 patients (51%), and the recurrent site was confirmed by PET alone in 17 (37%). PET had high sensitivity for detecting both intraperitoneal and retroperitoneal metastases (93.9 and 92.9%, respectively). PET imaging was able to detect normal-sized metastases in the lymph nodes in 14 (50%) of the 28 patients with retroperitoneal metastasis. PET could show 87.5% positive rate of recurrent patients with asymptomatic rise of CA125 who had no sign of recurrence by conventional imaging methods. Of the 46 recurrent patients, 41 (89%) had specific elevated titers of CA125 at the first treatment. PET imaging was able to detect recurrence at relatively low titers (a median 68 U/mL) of CA125. In 8 (19.5%) of these 41 patients, recurrence with normal CA125 levels could be confirmed only by PET. The sensitivity of the combination of PET and CA125 was 97.8% with only one false-negative case. The combination of FDG-PET and CA125 titer is useful for the accurate detection of recurrence.
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