The ovaries are two small glands that make up part of the female reproductive system. They have two main functions: to produce and store eggs for reproduction, and to produce the female sex hormones oestrogen and progesterone.
Ovarian cancer occurs when abnormal cells in the ovary start to multiply, creating a tumour. If the tumour is malignant it is cancerous and, left unchecked, may grow and spread to other parts of the body.
Types of ovarian cancer
There are three types of ovarian tumour: epithelial, germ cell and sex-cord stromal.
Around 90% of ovarian cancer tumours are epithelial, the majority of which are known as serous epithelial ovarian cancer. These tumours occur most commonly in women between the ages of 40 and 60.
Stages and grades of ovarian cancer
When a woman is diagnosed with ovarian cancer she will be told what stage it is at. The stage represents how far the cancer has spread inside her body.
There are four stages of ovarian cancer. At stage 1 the cancer is contained within one, or both of the ovaries. As the stages progress the cancer will spread further. By stage 4 it may have reached places such as the liver, the lungs and the brain. The earlier the cancer is diagnosed the easier it is to treat.
A woman who is diagnosed with ovarian cancer will also be told what grade the tumour is. Grading predicts how quickly the tumour is expected to spread.
For more information on ovarian cancer tumours, or to find out more about stages and grades, download our guide: Ovarian cancer: what you need to know.