The effect of preoperative imaging methods (MR, CT, 18F-FDG PET/CT) on determining the propagation of ovarian cancer and determining the treatment method

OBJECTIVE: Epithelial ovarian cancer is the most common ovarian carcinoma and it usually shows a peritoneal spread pattern in its advanced stages. Proper surgical cytoreduction is an important independent factor that affect survival. Therefore, the purpose of surgery is to completely remove the existing tumor tissue. Neoadjuvant Systemic Chemotherapy (NACT) option is considered when adequate cytoreduction is not possible. The sites of metastases have crucial effect on choice of primary treatment. Our primary goal is to determine the imaging method which is more successful in demonstrating intra-abdominal tumoral volume and tumor infiltrating areas prior to the operation in patients with EOC. Sensitivity-specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy percentages of each imaging method were determined in detecting tumors in 24 specific anatomical regions in which EOC frequently spreads. Our secondary goal is to determine the efficacy of all three imaging modalities in calculating the International Peritoneal Cancer Index (PCI) score recommended by Sugarbaker. Therefore, we compared the pre-operative PCI score calculated with imaging methods and the PCI score calculated during the operation. Our tertiary aims is to determine the sensitivity and specificity of each method in detecting the tumoral implants in the anatomic regions of the Leuven criteria which are used to decide the primary treatment of EOC. MATERIALS AND METHODS: The name of our study is 'The Effect of Preoperative Imaging Methods (MRI, CT and 18F-FDG PET / CT) on Determining the Propagation of Ovarian Cancer and Determining the Treatment Method'. Twenty-four patients who were diagnosed with EOC (primary, recurrence or NACT) by Istanbul University, Istanbul Faculty of Medicine, Department of Gynecological Oncology between 2017-2018 were included in this study. All patients underwent three imaging procedures shortly before the operation and the patients were operated. The data obtained during the surgery and the data obtained from all three imaging methods were compared statistically. RESULTS: When we look at 24 specific anatomical regions in which metastases of ovarian cancer is common, the sensitivity of MRI, CT, 18F-FDG PET/CT methods in detecting implants greater than 0,5 cm was 95%, 84% and 86%, respectively. For all dimensions including millimetric implants, the sensitivities were 40%, 38% and 42%, respectively. A statistically significant difference was found between the PCI score calculated by imaging methods and the PCI score obtained from the surgical results. No statistically significant difference was found between the three imaging methods compared to each other. In the anatomical regions of the Leuven criteria, MR sensitivity was 67%, CT sensitivity was 67%, and 18F-FDG PET/CT sensitivity was 83%. CONCLUSION: MRI, CT, 18F-FDG PET/CT have high sensitivity to show lesions which equal or greater than 0,5 cm. However, they can't detect the diffuse disease including lesions smaller than 0,5 cm and they fail to calculate the PCI score before the operation. The sensitivity of 18F-FDG PET/CT was found to be relatively higher in the detection of the regions under the Leuven criteria. According to our study; The contribution of using different imaging modalities at the same time is minimal in deciding the primary treatment of advanced EOC and determining its spread for the abdomen. Instead of using different imaging methods at the same time, diagnostic laparoscopy may be considered as an option.