This is a prospective,multi-centre study involving serial blood collections from 100 stage I-IV debulked (or to be debulked in the case of neoadjuvant chemotherapy) high grade serous, endometrioid and clear cell ovarian, fallopian tube and primary peritoneal cancer patients (EOC) or ovarian carcinosarcoma planned to receive adjuvant chemotherapy. Tumour samples will be made available following patient enrollment for the primary debulking group, and following surgery for the neoadjuvant group for mutation analysis. Ascites will not be accepted. Up to four blood samples in the primary debulking group and up to five blood samples in the neoadjuvant group will be collected from each patient over a 6-8 month period for ctDNA and Ca125 analysis Choice of chemotherapy will be platinum based treatment at the treating clinician's discretion as per standard of care.
