Diagnosis and staging of primary ovarian cancer: Correlation between PET/CT, Doppler US, and CT or MRI

Purpose: To compare the diagnostic accuracy of positron emission tomography/computed tomography (PET/CT), pelvic Doppler ultrasonography (US), abdomino-pelvic computed tomography (CT), and pelvic magnetic resonance imaging (MRI) for detection of ovarian cancer and to assess the role of PET/CT in evaluating the dissemination of ovarian cancer. Patients and Methods: One hundred thirty-three women suspected to have ovarian cancer were enrolled in a prospective study before surgery between March 2005 and August 2007. The accuracy of each modality in detection of malignancy was estimated by computing the relevant areas under a receiver operating characteristics curve. Histopathologic results served as the reference standard. Results: Histopathology showed benign tumors in 25 patients, borderline tumors in 13 patients, and malignant tumors in 95 patients. In distinguishing malignant/borderline from benign ovarian tumors, the accuracy of PET/CT (0.921) was higher than that of pelvis US (0.830) and abdomino-pelvic CT or pelvis MRI (0.749; P = 0.013). Radiologic staging by PET/CT was concordant with surgical staging in 78% of patient and PET/CT revealed 15 (15.8%) unpredicted extra-abdominal lymph node metastasis in 95 patients with ovarian cancer. In addition, PET/CT detected new, unexpected co-existing malignant tumors in five (3.8%) cases including two thyroid tumors, two breast tumors, and one pancreatic neuroendocrine cancer. Conclusion: PET/CT is superior to pelvis US, abdomino-pelvic CT, and pelvic MRI for diagnosis of malignant ovarian tumors and is useful in revealing metastatic ovarian cancer and co-existing malignant tumors. Therefore, we suggest that PET/CT could be used during pre-operative evaluation of patients suspected to have ovarian cancer.