Women sat down discussing information about ovarian cancer

What is ovarian cancer?

Find out what cancer is, and how ovarian cancer is explained in terms of type, sub type, stage and grade.

What is cancer?

Our bodies are made up of millions of cells. Our body is constantly replacing worn out cells with new ones, either to maintain good health or when we hurt ourselves (for example, get a cut or graze).

When our body destroys an old cell, one of the remaining cells will make a copy of itself by dividing into two, replacing the old cell. This process is usually carefully controlled so that the number of new cells created is the same as the number that were destroyed.

However, sometimes a cell can go out of control and can't respond to the signals that tell it to stop dividing. The cell divides again and again, making more and more copies of itself, eventually forming a lump called a tumour. When these tumours grow uncontrollably and invade surrounding tissues or spread further away, this is termed cancer.


A tumour (also known as a neoplasm) is any abnormal mass of tissue (collection of cells). Like a cyst, a tumour can form in any part of the body. A tumour can be benign (non-cancerous), malignant (cancerous) or borderline (between malignant and benign).

Benign (non-cancerous) tumours may cause symptoms but in most cases they don't come back after surgical removal (having an operation). Cells in benign tumours don't spread to other parts of the body.

Malignant (cancerous) tumours are made up of cells that grow out of control. Cells in these tumours can invade nearby tissues and spread to other parts of the body.

Sometimes cells move away from the original (primary) cancer site and spread to other organs and areas through the bloodstream or the lymphatic system (tiny vessels similar to blood vessels passing clear fluid towards the heart) where they can continue to grow and form another tumour at that site. This is known as metastatic or secondary cancer. Metastases keep the name of the original cancer location, so ovarian cancer that has spread to the liver is still called ovarian cancer.

Borderline tumours are rare types of growth, and although the cells look abnormal they rarely have the tendency to grow out of control.

To determine whether a cyst or tumour is benign or malignant, a sample of the affected tissue – or in some cases the entire suspicious area – is removed and studied under a microscope. This is known as a biopsy.

Ovarian cancer

The ovaries are two small organs, each about the size and shape of an almond, located low in the tummy area called the pelvis, just behind the pubic area in women. They form part of a woman's reproductive and hormonal systems, storing a woman's supply of eggs. 

Diagram showing the location of the ovaries in the body
Diagram showing the location of the ovaries in the body

Each month an egg is released from one of the ovaries through the fallopian tubes into the womb ready for fertilisation. The ovaries are also responsible for making the female hormones oestrogen and progesterone. 

A close-up illustration of the ovaries, fallopian tubes, womb and vagina
A close-up illustration of the ovaries, fallopian tubes, womb and vagina

Ovarian cancer is cancer arising from the cells in and around the ovary and fallopian tubes. There are many different types of ovarian tumours classified by the types of cells and tissue they originate from.  

Ovarian cancer metastases or secondary cancers are lumps formed in other parts of the body because of the spread of ovarian cancer cells.

Ovarian cancer cells tend to spread on the surface of the tummy (abdomen) called the peritoneum (a large, thin, flexible sheet of transparent tissue that covers the organs inside your abdomen) and often form lumps on the surface of the bowels, the omentum (a fatty layer of tissue that extends downwards from the stomach), the liver surface and, rarely, within the liver, the spleen or the lungs. These lumps (metastases) often produce excess fluid in the tummy called ascites, which can cause significant bloating and uncomfortable symptoms. 

Side view of the body showing the ovaries and surrounding organs
Side view of the body showing the ovaries and surrounding organs

Understanding the type of cancer (the histotype), if and how it has spread (the stage), and the potential aggressiveness of the cancer (the grade) can help you when discussing your diagnosis, treatment and prognosis with your specialist. However, some women may not wish to know so much detail – it's a personal choice.

Last reviewed: June 2018

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