Stages and grades

When you're diagnosed, your medical team will aim to identify how much cancer there is, how far it's spread, and how fast it's likely to grow and spread.

Understanding if and how the cancer has spread (the stage) and how different your cancer cells look to normal cells (the grade) can help you when discussing your diagnosis, treatment and prognosis with your medical team. But you may not wish to know so much detail – it's a personal choice.


An international system of staging is used to look at how far the cancer has spread. This involves scans, examining you during surgery and taking some samples of tissue (biopsies). Finding out the stage of the cancer is an important part of diagnosis because it can affect your treatment options. This staging system is called the FIGO system, named after its authors, the International Federation of Gynaecological Oncologists (Fédération Internationale de Gynécologie et d'Obstétrique).

Use the tool below to find out about the different stages and substages of ovarian cancer. The tool shows staging for tumours that start in the ovaries and/or fallopian tubes and doesn’t show primary peritoneal cancer, which is treated in a similar way. Find out more about primary peritoneal cancer.

To get started click on the tabs along the top.

The stage of the ovarian cancer can impact your treatment. If you have any questions about the stages of ovarian cancer and what this means for you, our specialist nurses are here. Our support line is open Monday-Friday, 9-5pm. Call 020 7923 5475.


Grading refers to how similar cancer cells look to normal cells and can help predict how the cancer will behave. This includes how fast it's likely to grow and spread, which may impact on the treatments recommended for you

There are some ovarian tumours that rarely spread. These are called borderline or atypically proliferative tumours (not cancers). 

In the most common type of ovarian cancer the tumours are simply divided into low-grade and high-grade and a grading number isn’t given. The most common type of ovarian cancer is high-grade serous carcinoma. There is also low-grade serous, which is less common. High grade tumours are also more likely to respond to chemotherapy compared to low grade tumours. 

All other ovarian cancers are graded as 1, 2 and 3.  

  • Grade 1 (well differentiated) cancers have cells that closely look like normal cells and are less likely to spread or recur (come back).

  • Grade 2 (moderately differentiated) cancers and grade 3 (poorly differentiated) cancers show increasing difference of appearance compared to normal cells. They are also more likely to spread and recur (come back). 

Differentiation is the process by which cells change in structure and become specialised for their role and place in the body. Well differentiated tumours are highly specialised for their role and place. The cells and tissue structures are very similar to normal tissues. 

Last reviewed: April 2022

To learn more about our review process, take a look at our information standards.