About stages and grades of ovarian cancer

The stage of a cancer tells you how big it is and whether it has spread. The grade means how abnormal the cells look under a microscope. The stage and grade help your doctor decide which treatment you need.

Staging ovarian cancer

The tests and scans you have to diagnose your cancer will give some information about the size of your cancer. And whether it has spread (the stage). But your doctor might not be able to tell you the exact stage until you have surgery.

Doctors use a simple 1 to 4 staging system for ovarian cancer. It is called the FIGO system after its authors - the International Federation of Gynaecological Oncologists.

Grades of ovarian cancer

The grade of a cancer tells you how much the cancer cells look like normal cells. It gives your doctor an idea of how the cancer might behave. 

As a normal cell grows and matures, it becomes specialised for its role and place in the body. This is called differentiation. Cancer cells can look like normal cells. They are described as well differentiated or low grade. These cancers are more likely to grow slowly.

Cancer cells can also look underdeveloped and nothing like a normal cell. They are known as undifferentiated or high grade. These cancers tend to grow and spread more quickly than low grade cancers.

Grading systems

Doctors use different systems to grade ovarian cancer. It depends on your type of ovarian cancer.

They describe serous epithelial ovarian cancer as either high grade or low grade. This depends on how much the tumour cells look like normal tissue.

They describe other types of epithelial ovarian cancers as:

• grade 1 or well differentiated
• grade 2 or moderately differentiated
• grade 3 or poorly differentiated (or undifferentiated)

Main treatments for ovarian cancer

The main treatments for ovarian cancer are surgery and chemotherapy. Almost all women with ovarian cancer will need surgery. The amount and type of surgery you have will depend on your stage and type of cancer.

For some women with very early stage ovarian cancer, surgery is the only treatment you need.

Most women with ovarian cancer are diagnosed with advanced disease and have a combination of both surgery and chemotherapy. You may have chemotherapy after surgery, or both before and after surgery.