Hi mom has ovarian carcinoma with pertonial carcinomatosis and there are effusion in belvis abdomin and around lung . so what is the stage of cance?

Need more surgy info: The cancer is at least Stage IIIA1, but may be Stage IV depending on analysis of the effusion around the lung. See https://www.cancer.org/cancer/ovarian-cancer/detection-diagnosis-staging/staging.html. To stage the cancer, samples of tissues are taken from different parts of the pelvis & abdomen & examined under the microscope. But this cancer is widespread, so surgical staging may not be possible