Blood-Based Minimal Residual Disease in Advanced Epithelial Ovarian Cancer After 1st Line Therapy

The purpose of this observational study is to learn if a specialized blood test can help predict whether advanced ovarian cancer will return after a patient's initial treatments are finished. Researchers are inviting women who have been diagnosed with stage III or IV epithelial ovarian cancer and have recently completed their first-line treatments, which include surgery and platinum-based chemotherapy. The study focuses on "circulating tumor DNA" (ctDNA), which are tiny fragments of genetic material that cancer cells release into the bloodstream as they break down. Finding these DNA fragments in the blood when a patient appears to be cancer-free on standard tests is known as assessing for minimal residual disease (MRD). Because this is an observational study, participants will receive standard medical care as directed by their doctor. For the research portion, participants will provide blood samples at specific times: at the time of diagnosis, shortly after surgery, right after finishing their first-line chemotherapy, and then every 3 months during regular follow-up visits. Researchers will also analyze a sample of the tumor tissue that was already removed during the patient's standard surgery. By tracking these participants for up to 3 years, researchers hope to discover if the ctDNA test can accurately identify patients who have a high risk of their cancer returning, and if it can detect this earlier than traditional imaging scans or standard blood tests like CA-125.

Inclusion Criteria: Women aged 19 years or older. Pathologically confirmed high-grade serous, endometrioid, clear cell, or mixed type ovarian cancer. FIGO stage III or IV. Patients who have completed primary debulking surgery (PDS) or interval debulking surgery (IDS) and platinum-based chemotherapy (subsequent maintenance therapy, such as bevacizumab or PARP inhibitors, is allowed). Patients showing radiological or clinical Complete Response (CR) after the completion of platinum-based chemotherapy. Written informed consent for the study. Exclusion Criteria: Radiological progressive disease during or immediately after treatment. Expected survival of 3 months or less. Immunodeficiency or pathological bleeding tendencies. Unable to undergo blood tests or unwilling to undergo repeated blood sampling. Concurrent other solid tumors or history of malignant tumors within the last 5 years. Refusal to consent to participate in this study.