الفهرس 
ANATOMY OF THE OVARYOnly 14 pages are availabe for public view
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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.
PET/CT had the advantage of whole body scanning, thus it is more helpful in cases with suspicious of recurrence other than abdominal metastases. Further studies are required to assess role of PET/CT in the change of management of patients with ovarian cancer and to determine whether if alter patients survival and quality of life (Tawakol et al., 2015).
PET scan which exploits the increased utilization of glucose by malignant cells opened a new field in clinical oncologic imaging.
Integrated PET/CT acquires both metabolic and anatomic imaging data using a single device and provides precise anatomic localization of suspicious areas of increased FDG uptake. In the clinical setting, FDG-PET/CT has achieved a significant improvement in diagnostic accuracy and exerted a considerable impact on patient management including diagnosis, staging, optimization of treatment, restaging, therapy monitoring, and prognostic prediction of various malignant tumors.
The available data in the literature regarding these benefits are growing, but yet not conclusive in demonstrating a clear advantage of FDG PET/CT over conventional imaging such as ultrasound, contrast-enhanced CT and magnetic resonance. This has resulted in FDG PET/CT being excluded in the most recent international guidelines, despite its good results Currently, the most frequent indication for FDG PET/CT remains the detection of recurrence in an already radically treated patient with rising Ca-125 levels and negative conventional imaging (Avril et al ., 2011). However, PET/CT proved also to be useful in post treatment tumor surveillance when tumor markers are within normal reference range.
In the current study we evaluated the role of PET/CT in 30 patient with 30 total numbers of scans. Our results showed that PET/CT showed high sensitivity, specificity and accuracy for local pelvic recurrence and pelvic lymph nodes (on lesion-site based analysis), as well as of relatively lower specificity in peritoneal deposits which were concordant with previous studies in diagnosis of recurrence (normal or abnormal tumor marker levels). We suggest that PET/CT could decrease rate of second look surgery and change the treatment plan in post primary treatment tumor surveillance when there is suspicious clinical or biochemical recurrence.
Moreover, PET/CT as a whole body imaging technique can detect more extra-abdominal sites of disease than do conventional studies.
Metabolic changes often precede morphologic changes in tumor recurrence and therefore FDG-PET can demonstrate this recurrence sooner than conventional studies, thus significantly improve patient management by reducing the delay before administering of effective treatment.
Our study and Lin et al., 2011 noticed that:
1- PET/CT is most accurate when conventional imaging is inconclusive and CA-125 is elevated.
2- Second look laparotomy is still necessary if recurrence is strongly suggested because the sensitivity of PET/CT in diagnosis of tiny and small lesions (eg: sub-serosal peritoneal nodules) is relatively of lower sensitivity and specificity compared to 2nb look laparotomy however PET/CT can change the management due to high predictive value.
3- The sensitivity of PET/CT depend on clinical suspicion, PET/CT is sensitive if there is high clinical suspicion of recurrence, particularly if this suspicion is based upon the rising CA-125 levels.
4- PET/CT is more sensitive in the pelvic recurrence, in retroperitoneal than peritoneal, in lymph node metastasis than peritoneal metastasis.