Introduction: Who Should Undergo Diagnostics

If you’re experiencing symptoms that could point to ovarian cancer, it’s important to seek medical attention without delay. Stage 3 ovarian cancer often reveals itself through persistent symptoms that may initially seem unrelated to a serious condition. These can include ongoing pelvic or abdominal pain, bloating that doesn’t go away, changes in eating habits such as feeling full quickly or losing your appetite, and unusual bowel changes like diarrhea or constipation.^[1][4]

Women who notice these symptoms lasting for more than a few weeks should schedule a visit with their healthcare provider. Because ovarian cancer can develop and spread throughout the abdomen before causing noticeable symptoms, early detection can be challenging.^[4] By the time many women are diagnosed, about 60 percent already have stage 3 disease.^[6] This doesn’t mean the situation is hopeless, but it does highlight why paying attention to your body and seeking help when something feels wrong is so important.

Certain groups of women face higher risk and should be especially vigilant. If you’re over the age of 60, have a family history of ovarian cancer, carry a BRCA gene mutation (an inherited change in your genes that increases cancer risk), or have conditions like endometriosis, you should discuss screening options with your doctor.^[4] Women of Ashkenazi Jewish descent have a higher likelihood of carrying BRCA mutations, placing them at increased risk for both breast and ovarian cancer.^[4]

Diagnostic Methods for Stage 3 Ovarian Cancer

When your doctor suspects ovarian cancer, they will begin with a thorough evaluation. The diagnostic process typically starts with a conversation about your symptoms and a pelvic exam, during which the doctor checks for any abnormal growths or enlarged organs.^[4] However, a pelvic exam alone cannot definitively diagnose ovarian cancer or determine its stage. Additional tests are necessary to build a complete picture.

Imaging Tests

Imaging tests allow doctors to see inside your body without surgery. Several types of imaging may be used to evaluate suspected ovarian cancer. A pelvic ultrasound is often one of the first tests performed. This test uses sound waves to create pictures of your ovaries and surrounding structures, helping doctors identify masses or abnormal fluid collections.^[4]

More detailed imaging may include a CT scan (computed tomography), which takes cross-sectional images of your abdomen and pelvis. A CT scan can show whether cancer has spread to the peritoneum (the lining of your abdominal cavity), lymph nodes, or other organs.^[4] An MRI (magnetic resonance imaging) uses magnets and radio waves to create detailed images of soft tissues and may help distinguish between different types of masses.^[4]

A PET scan (positron emission tomography) is sometimes used to detect cancer that may have spread beyond the ovaries. This test involves injecting a small amount of radioactive sugar into your bloodstream. Cancer cells, which use more energy than normal cells, absorb more of this sugar and show up as bright spots on the scan.^[4] These imaging tests work together to help your medical team understand where the cancer is located and how far it has traveled.

Blood Tests

Blood tests can provide important clues about the presence of ovarian cancer. The most commonly used blood test looks for a substance called CA-125. This is a protein that can be elevated in the blood of women with ovarian cancer.^[4] However, CA-125 levels are not always reliable on their own. Some women with ovarian cancer have normal CA-125 levels, while others without cancer may have elevated levels due to other conditions such as endometriosis, fibroids, or even menstruation.^[4]

Because of these limitations, doctors use CA-125 results in combination with other tests rather than relying on them alone. If your CA-125 level is high and imaging shows suspicious masses, your doctor will likely recommend further investigation. Blood tests may also be repeated over time to monitor how the cancer responds to treatment.^[4]

Surgical Evaluation and Staging

The most definitive way to diagnose ovarian cancer and determine its exact stage is through surgery. Your doctor might not be able to tell you the precise stage until you have undergone a surgical procedure.^[1] During surgery, doctors can directly see how far the cancer has spread and take tissue samples for laboratory analysis.

A laparoscopy is a minimally invasive surgical procedure where a thin tube with a camera is inserted through a small cut in your abdomen. This allows the surgeon to examine your organs and take tissue samples, called biopsies.^[4] If abnormal growths are found during laparoscopy or other surgical procedures, they are often removed and sent to a lab, where a specialist examines them under a microscope to confirm whether cancer is present and what type it is.^[4]

For stage 3 ovarian cancer, doctors use a staging system developed by the International Federation of Gynecology and Obstetrics (FIGO). This system helps classify the cancer based on where it has spread.^[1][3] Stage 3 is divided into substages:

• Stage 3A1 means the cancer has spread to lymph nodes in the back of your abdomen, called retroperitoneal lymph nodes. This is further divided based on the size of cancer in the lymph nodes: 3A1(i) means the cancer in the lymph nodes is smaller than 1 centimeter, while 3A1(ii) means it is larger than 1 centimeter.^[1]
• Stage 3A2 means there are cancer cells in the peritoneum that can only be seen under a microscope. Cancer might also be in your lymph nodes.^[1]
• Stage 3B means there are visible cancer growths in the peritoneum that are 2 centimeters or smaller. There might also be cancer in the retroperitoneal lymph nodes.^[1]
• Stage 3C means there are cancer growths in the peritoneum larger than 2 centimeters. There might also be cancer in your lymph nodes or on the surface of your spleen or liver.^[1]

During surgery, the surgeon collects tissue samples from different parts of your pelvis and abdomen. They also rinse the abdomen with a salt water solution and collect the fluid, called pelvic washings, to check for cancer cells.^[14] All of these samples are analyzed in a laboratory to determine the exact extent of the cancer. This comprehensive evaluation is called surgical staging.^[1]

If surgery is not immediately possible—perhaps because the cancer has spread too widely or you are not well enough—doctors assign a clinical stage based on imaging tests and physical exams. Later, if you undergo surgery, the stage may be updated based on what is found during the procedure.^[3]

Diagnostics for Clinical Trial Qualification

If you are considering participating in a clinical trial—a research study testing new treatments—you will need to meet specific criteria, which often include particular diagnostic tests. Clinical trials are designed to test new therapies, drug combinations, or treatment approaches that may improve outcomes for patients with stage 3 ovarian cancer. Before you can join a trial, researchers need to confirm that you meet the study requirements.^[1]

Standard diagnostic criteria for enrolling in clinical trials typically include confirmation of your cancer stage through surgical staging or imaging tests. Your medical team will need to document where the cancer has spread and whether it fits the trial’s inclusion criteria. For example, some trials may only accept patients with stage 3C disease, while others may include all stage 3 substages.^[1]

Blood tests, including CA-125 levels, are commonly used as baseline measurements before starting a clinical trial. These results help researchers monitor how well the experimental treatment is working over time. Imaging tests such as CT scans or MRIs may also be repeated at regular intervals during the trial to track changes in tumor size and spread.^[4]

Some clinical trials may require additional specialized tests. For instance, if the trial involves a targeted therapy—a treatment designed to attack specific characteristics of cancer cells—you may need genetic testing or biomarker testing. These tests analyze your tumor tissue to look for specific mutations or proteins that the experimental drug is designed to target.^[2]

One example is testing for BRCA mutations. If genetic testing reveals that you have a BRCA mutation, you might be eligible for maintenance medications called PARP inhibitors, which are given after chemotherapy to help keep you in remission.^[20] Clinical trials often test new PARP inhibitors or combinations of existing ones, and having this genetic information is essential for determining your eligibility.

Your general health status is also evaluated before entering a clinical trial. This typically involves blood tests to check your kidney and liver function, as well as your blood cell counts. These tests ensure that your body can tolerate the experimental treatment without experiencing dangerous side effects.^[4]

If you’re interested in clinical trials, talk to your healthcare team about what trials are available and what diagnostic tests you might need to qualify. Participating in a clinical trial can give you access to cutting-edge treatments that are not yet widely available, and it also contributes to research that may help future patients.^[1]