MR-PET for Staging and Assessment of Operability in Ovarian Cancer - a Feasibility Study

The importance of selecting patients with ovarian cancer who will benefit from either primary debulking surgery or neoadjuvant chemotherapy followed by interval debulking surgery has been acknowledged worldwide but the optimal diagnostic modality to serve in this matter remains to be discovered. We believe that combined magnetic resonance imaging and positron emission tomography (MR-PET) can be of great clinical value in preoperative staging of patients with ovarian cancer.

Recently, the academic hospital Maastricht invested in an integrated MR-PET system (Biograph mMR, Siemens Healthcare, Erlangen, Germany), ready to use for routine clinical application. Applications of this system are numerous and various types of cancer, including ovarian cancer, could benefit from the possibilities. The whole-body MR-PET system integrates the strengths of MRI and PET within a single examination. MRI provides anatomic detail in staging local tumor extent due to its high soft tissue resolution and advanced functional techniques such as DWI further enhance both local and distant lesion detection and characterisation. PET imaging complements this structural and functional information with molecular imaging technology useful in staging of adenopathy and metastatic spread. These characteristics contribute to a wide spectrum of possible clinical oncological applications, from primary tumor detection to local and distant staging, selection of patients for neoadjuvant therapy and assessment of response to chemotherapy and finally evaluation of recurrent disease. The importance of selecting patients with ovarian cancer who will benefit from either primary debulking surgery or neoadjuvant chemotherapy followed by interval debulking surgery has been acknowledged worldwide but the optimal diagnostic modality to serve in this matter remains to be discovered. We believe that combined magnetic resonance imaging and positron emission tomography (MR-PET) can be of great clinical value in preoperative staging of patients with ovarian cancer. Both positron emission tomography (PET), computed tomography (CT) and magnetic resonance imaging (MRI) have proved to be useful in ovarian cancer staging but understaging due to difficulties in depicting peritoneal dissemination remains a great problem. In conclusion, the best method for staging ovarian cancer and assessing operability remains to be discovered, hence this study.

The MR-PET will be performed with the Biograph mMR system (Siemens Healthcare, Erlangen, Germany). This system integrates a 3Tesla MRI and PET scan which makes simultaneous acquisition of whole-body MRI and PET images possible. The Biograph mMR holds the CE mark and was FDA approved in June 2011. The Biograph mMR is intended to be used in the Academical hospita! Maastricht for standard patient care. The radiotracer that will be used is 18F-Iabeled fluorodeoxyglucose (18F-FDG), according to standard PET -protocol.

Diagnostic performance of MR-PET compared to CT for characterisation of primary tumour, detection of tumour sites in the peritoneal cavity, retroperitoneum or liver, detection of lymphadenopathy and distant metastases and assessment of tumour stage and operability.

Inclusion Criteria: Expected FIGO stage IIB-IV epithelial ovarian carcinoma Scheduled for primary debulking or interval debulking surgery Written informed consent Exclusion Criteria: Patients estimated to have more benefit from chemotherapy Ineligibility to undergo MR-PET examination (Non-MR compatible metallic implants or foreign bodies (ferromagnetic aneurysm clip, pacemaker, neurostimulation system, metal splinters etcetera) or claustrophobia) Pregnant or lactating patients. Incapacitated subjects

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