The aim of the study is the assessment of tumour sites critical for the achievement of optimal cytoreduction in patients with advanced ovarian cancer using Ultrasound, CT and WB-DWI/MRI. The study uses an equivalence design with a hypothesis that cases with non-resectable disease identified by Index test (Ultrasound, CT and WB-DWI MRI) are equivalent to a portion of cases identified during surgery.

Patients with abdominal or pelvic mass suspicious of primary ovarian, tubal or peritoneal cancer using subjective assessment by experienced sonographer (principal investigator) will be enrolled in the study and send to surgical planning. During surgical planning, the CT and MRI will be scheduled and the patient ́s consent will be requested if inclusion criteria are fulfilled. Please note, tumors with atypical morphology and/or tumor spread suspicious for secondary ovarian cancer will be first subjected to a tru-cut biopsy and will be included if histopathology confirms adnexal or peritoneal cancer.

Ultrasound will be always performed by the principal investigator in each center. Principal investigator is an ultrasound expert with level II or III EFSUMB accreditation (http://www.efsumb.org/). Operators performing ultrasound scan and radiologists performing CT or MRI will be well instructed and educated about standardized approach and criteria of inoperability. Sonographers and radiologists will be blinded to the results of other imaging modalities. If a patient already had CT or WB-DWI/MRI done by the referring hospital, the study radiologists will decide about the quality of imaging and necessity to repeat CT or WB-DWI/MRI.

The decision to treat by PDS (primary debulking surgery), or by NACT (neoadjuvant chemotherapy) with IDS (interval debulking surgery) will be based on departmental guidelines taking into account medical comorbidities and disease-related factors. If a patient is indicated for NACT a tru-cut biopsy or/and a diagnostic laparoscopy are performed. The clinicians will document why the primary debulking surgery was not considered. The surgery (laparoscopy, primary or interval debulking surgery) should always be performed within four weeks after the index test. Patients without surgical exploration will be excluded.

Surgeons performing laparoscopy will describe site to site involvement and in case of inoperability will take a biopsy and document reasons for abandoning laparotomy. In operable cases surgeons performing laparotomy will describe site to site involvement and where applicable reasons for not achieving optimal cytoreduction defined as no residual tumor left in situ at the end of surgery (R0).

If the patient has only ultrasound and CT (and not WB-DWI/MRI) she can still be included in the study. Similarly if the patient undergoes interval debulking surgery she can be included in the study if the index tests will be performed less than 4 week before IDS.

Clinical data and four evaluation forms will be filled in (Ultrasound, CT, MRI, Surgery) immediately after the procedure using electronic database. The evaluation form from histopathology will be filled when available by principal investigator. The database cannot be saved unless all the information required are filled in and it will not be available to any other investigator. Data will be submitted for statistical analysis.

Inclusion Criteria:

1. Abdominal or pelvic mass suspicious of primary ovarian, tubal or peritoneal cancer using subjective assessment by experienced sonographer.
2. Surgery (PDS or IDS) within 4 weeks from the index test.
3. 18 > Age < 80.
4. ECOG (Eastern Cooperative Oncology Group) grade < 3.
5. Patients after NACT can be included.

Exclusion Criteria:

1. Lesions suspected as being borderline ovarian tumors (BOT) on ultrasound.
2. Patients with supradiaphragmatic metastases
3. Contraindications to CT
4. Medical contraindications to surgery
5. Refusal or withdrawal of written informed consent
6. Time lapse between ultrasound and surgery more than 4 weeks
7. Current pregnancy

Female patients

Patients with an abdominal or pelvic mass suspicious of primary ovarian, tubal or peritoneal cancer