Staging and grading of ovarian cancer
The stage and grade of ovarian cancer, fallopian tube cancer and primary peritoneal cancer describes its size, whether it has spread and how quickly it may grow.
Staging cancer of the ovary, fallopian tube or peritoneum
The stage of a cancer describes where the cancer has been found and other places it may have spread to. Knowing the stage helps your doctors plan the best cancer treatment for you.
Your doctor will not usually know the exact stage of the cancer until it has been removed with surgery. If you have not had surgery, they can use test results, such as your CT scan, to decide the stage of the cancer.
Doctors use the International Federation of Gynecology and Obstetrics (FIGO) staging system to stage ovarian cancer, fallopian tube cancer and primary peritoneal cancer. This system uses numbers and letters to describe different stages of ovarian cancer.
Stage 1
This is early stage cancer.
Stage 1a
The cancer is only in 1 ovary or fallopian tube.
Stage 1b
The cancer is in both ovaries or both fallopian tubes.
Stage 1c
The cancer is in 1 or both ovaries or fallopian tubes. One or more of the following has also happened:
- The surrounding tissue (capsule) of the ovary or fallopian tube has broken. This may have let cancer cells leak into the tummy or pelvis.
- There are cancer cells on the surface of the ovaries or fallopian tubes.
- There are cancer cells in the fluid in the tummy or pelvis.
Stage 2
The cancer is in 1 or both ovaries or fallopian tubes and has grown into nearby areas inside the pelvis.
Or, the cancer has started in the peritoneum but only affects areas inside the pelvis.
Stage 2a
There is cancer on the womb, fallopian tubes or ovaries.
Stage 2b
There is cancer on other structures in the pelvis, such as the bowel or bladder.
Stage 3
The cancer is in 1 or both ovaries or fallopian tubes, or in the peritoneum. It has also spread to:
- the lymph nodes at the back of the tummy (abdomen). These are called the retroperitoneal lymph nodes
- the peritoneum outside the pelvis.
Stage 3a1
The cancer has spread to the lymph nodes in the tummy.
Stage 3a2
Very small amounts of cancer have spread to the peritoneum, outside the pelvis. There may also be cancer in the lymph nodes in the tummy area (abdomen).
Stage 3b
There are areas of cancer on the peritoneum, outside the pelvis. These areas are less than 2cm in diameter. There may also be cancer in the lymph nodes in the tummy.
Stage 3c
There are areas of cancer on the peritoneum, outside the pelvis, that are larger than 2cm in diameter. There may also be cancer in the lymph nodes in the tummy. The cancer may have spread to the capsule surrounding the liver and spleen, but not inside these organs.
Stage 4
The cancer has spread to other parts of the body outside the tummy.
Stage 4a
The cancer has caused a build-up of fluid in the lining of the lungs (the pleura). This is called a pleural effusion.
Stage 4b
The cancer has spread to the inside of the liver or spleen. Or the cancer has spread to lymph nodes or organs outside the tummy, such as the lungs.
Grading cancer of the ovary, fallopian tube or peritoneum
Grading describes how the cancer cells look under the microscope compared with normal cells. Knowing the grade helps your doctors plan your treatment options.
This is how ovarian, fallopian tube and primary peritoneal cancers are graded:
- Grade 1 (Low grade or well differentiated) – The cancer cells look very like normal cells. They usually grow slowly and are less likely to spread.
- Grade 2 (Moderate or intermediate grade) – The cancer cells look more abnormal. They are slightly faster growing.
- Grade 3 (High grade or poorly differentiated) – The cancer cells look very different from normal cells. They usually grow more quickly.
Epithelial ovarian cancer is the most common type of cancer to start in the ovary, fallopian tube or peritoneum. Most epithelial ovarian cancers are high-grade serous ovarian cancers.
Doctors think most high-grade serous ovarian and peritoneal tumours start at the very end of the fallopian tube. The cancer cells then spread to the ovaries and peritoneum.
Doctors do not stage or grade borderline tumours. This is because they are made up of abnormal cells rather than cancer cells.
About our information
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References
Below is a sample of the sources used in our ovarian cancer information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk
Ledermann, Raja, Fotopoulou et al. Newly diagnosed and relapsed epithelial ovarian carcinoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology, 2013; Volume 24, Supplement 6. Updated online 2020. Available from www.esmo.org/guidelines (accessed July 2021)
Management of epithelial ovarian cancer. Scottish Intercollegiate Guidelines Network (SIGN). Nov 2013 revised 2018. Available from www.sign.ac.uk.
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Reviewers
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.
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