The Role of PET/CT Imaging in the Evaluation of Recurrent Ovarian Cancer

Abstract

Ovarian cancer is the 5th cancer for both incidence and death among women. Despite high response after initial treatment (cytoreductive surgery and adjuvant chemotherapy), 20–30% of patients with early-stage disease and up to 75% of patients with advanced disease present with recurrence within two years (Gouhar et al., 2013). Early diagnosis of recurrence is important for planning future therapeutic strategies. It aims either to cure or to prolong disease-free survival and to improve the quality of life (Gouhar et al., 2013). Ovarian cancer spreads through the peritoneum, lymphatic system, and bloodstream. The peritoneum is the most frequent route of disease spread because 80% of ovarian tumors are originating from the epithelial surface of the ovaries. Detection of peritoneal implants generally depends on their size and on the presence of ascites (Funicelli et al 2010). These tumor implants can be very small with attenuation similar to surrounding viscera at computed tomography (CT), which makes their detection challenging. CT and MRI are the most commonly used imaging modalities in patients with suspected recurrent ovarian cancer, but small local recurrence, LN metastasis, small dissemination, and bone/muscle metastasis are difficult to detect with CT and MRI. PET/CT is a useful tool for evaluating recurrence of ovarian cancer after first-line therapy in patients with high risk of relapse, negative or equivocal radiologic findings, elevated or even non-elevated levels of serum Ca125. It can more accurately diagnose and localize recurrence, hence decreasing the rate of second look surgery and changing treatment plan (Gouhar et al 2013) & (Tawakol et al., 2015). Early diagnosis of recurrence and exact anatomic localization of metastatic disease are crucial for determination of the best treatment strategy. Even though the CA-125 tumor marker has high sensitivity for early diagnosis of recurrence in epithelial ovarian cancer; it does not give any information about the extent or location of recurrence. Moreover, it has a poor negative predictive value.