All participating women will be identified through the ovarian cancer audit implemented by the "Oncological Network of Piedmont and Valle d'Aosta" and the Clinical Epidemiology Unit of CPO Piemonte between 2015 and 2020. Women with EOC, and the center where they have been treated for the tumor, will be identified by linking the databases of the "Oncological Network of Piedmont and Valle d'Aosta" with those of the "Prevenzione Serena" project.
A few clinical information from EOC patients will be collected by clinical investigators at each center using an electronic case report form (e-CRF) developed at the Mario Negri Institute. These information will include age, date of diagnosis, histological subtype and grading, tumor stage according to FIGO 2014 classification2,3, previous gynecologic conditions and surgical operations, date of Pap Test collection, and Pap Test cytological reports. Participants' data will be identified by a unique patient code.