What Are the Stages of Ovarian Cancer?

Medically Reviewed by Minesh Khatri, MD on May 14, 2023
3 min read

Your ovaries are two almond-shaped organs that make female hormones and store eggs. If you have ovarian cancer, abnormal (cancerous) cells have been found inside one or both of them.

After you’re diagnosed, your doctor will explain what stage of cancer you have. This data helps doctors treat you. It will also give you a better idea of what’s going on inside your body.

“Staging” is the term doctors use to describe the size and location of a tumor. This includes where it started, if it’s spread, and where it is now. For ovarian cancer, doctors figure out your stage by testing tissue samples from different parts of your pelvis and belly.

This information helps your doctor better predict the best way to treat your cancer. Staging needs to be very precise. If not, a cancer that’s spread outside your ovaries might be missed.

Some medical groups may stage things in a slightly different way. The FIGO system by the International Federation of Gynecological Oncologists is a commonly used staging system.

Stage I is the least advanced stage of ovarian cancer. It means cancer is only in your ovaries or fallopian tubes. Within this group is:

Stage IA: Cancer is confined to inside only one ovary.

Stage IB: Cancer is inside both your ovaries.

Stage IC: Cancer is present in both ovaries. Plus, one of these has happened:

  • Stage IC1: During surgery to remove your tumor, cancer cells have leaked into your belly or pelvic area.
  • Stage IC2: Cancer on the outer surface of one of your ovaries or a fluid-filled tumor has burst and cancer cells have spilled into your belly before surgery.
  • Stage IC3: Lab tests have found cancer cells in fluid from your abdomen or pelvis.

Stage II cancer hasn’t spread to your lymph nodes or organs in distant parts of your body, but it has reached organs close to your ovaries.

Stage IIA: Cancer now is also in your uterus, fallopian tubes or both.

Stage IIB: Cancer has spread to organs in your pelvis like your bladder, colon, or rectum.

As well as nearby organs like your uterus and bladder, stage III cancer now is also in your stomach lining, the lymph nodes behind your belly, or both.

Stage IIIA1: Cancer is in your nearby lymph nodes and may be growing in nearby organs.

  • Stage IIIA1(i): The cancer in your lymph nodes is less than 10 millimeters (mm) across.
  • Stage IIIA1(ii): The cancer in your lymph nodes is bigger than 10 mm.

Stage IIIA2: Tiny cancer deposits are in your stomach lining, but can only be seen with a microscope. Cancer may also be in nearby lymph nodes.

Stage IIIB: Your doctor saw cancer growths in your belly during surgery, but they’re less than 2 centimeters (cm) across. They may also be outside your liver and spleen and in your lymph nodes.

Stage IIIC: This is like Stage IIIB except the cancer growths your doctor sees are larger than 2 cm.

The most advanced stage, stage IV signals that your cancer has spread to some distant organs.

Stage IVA: Cancer cells are in the fluid around your lung, but it hasn’t spread to any other areas outside your abdomen or pelvis.

Stage IVB: Cancer has been found inside lymph nodes, as well as tissues and organs. This may include your skin, lungs, or brain.

Talk with your doctor about what your stage means for your treatment and outlook. If you feel confused, anxious, or depressed, make sure to share your concerns and ask for support. You may want to talk with a counselor who works with people who have cancer, and you might want to join a support group.

Grading can help your doctor predict certain things about your cancer, such as how it will probably grow or spread. This may affect your treatment plan.

One type, serous epithelial ovarian cancer, is low-grade or high-grade. Other types have more detailed grades: Grade 1 (well-differentiated) cancers have cells that look a lot like normal cells and are less likely to spread or come back. Grade 2 (moderately differentiated) and grade 3 (poorly differentiated) cancers look more unusual and are more likely to spread or come back.