Ovarian cancer starts when cells in one or both ovaries, the fallopian tubes or the peritoneum become abnormal, grow out of control and can form a lump called a tumour.

Cancer of the fallopian tube was once thought to be rare, but recent research suggests that many ovarian cancers start in the fallopian tubes.

If ovarian cancer spreads from the ovaries, it is often to the organs in the abdomen and pelvis. It is common in some types of ovarian cancer for a large amount of fluid to build up in the abdomen (belly).

Sometimes an ovarian tumour is diagnosed as a borderline tumour (also known as a low malignant potential tumour). This tumour is not considered to be cancer but can still spread within the abdomen.

The ovaries

The ovaries are part of the female reproductive system, which also includes the fallopian tubes, uterus (womb), cervix (the neck of the uterus), vagina (birth canal) and vulva (external genitals).

The ovaries produce eggs. They also make the hormones oestrogen and progesterone, which control the release of eggs (ovulation) and the timing of periods (menstruation).

Ovaries are made up of:

• epithelial cells – found on the outside of the ovary in a layer known as the epithelium
• germ (germinal) cells – found inside the ovaries, which eventually mature into eggs (ova)
• stromal cells – form connective (supporting) tissue within the ovaries, and make the hormones oestrogen and progesterone.

The ovaries are two small, walnut-shaped organs. They are found in the lower part of the abdomen. There is one ovary on each side of the uterus, close to the end of each fallopian tube.

Other organs and structures near the ovaries include the:

• bladder – stores urine (pee)
• bowel – helps the body break down food
• rectum – stores faeces (poo)
• peritoneum – the lining of the abdomen
• omentum – the curtain of fatty tissue that hangs in front of the large bowel like an apron.

Ovulation and menstruation

Menopause

Types of ovarian cancer

There are many types of ovarian cancer. The three main types start in different cells found in the ovary.

Epithelial

Stromal cell (or sex cord-stromal tumours)

Germ cell

Non-cancerous ovarian tumour

Symptoms

The symptoms of ovarian cancer can be similar to other common conditions. This can make it difficult to diagnose early. Symptoms are more likely to develop as the cancer grows.

Symptoms for ovarian cancer include:

• pressure, pain or discomfort in the abdomen or pelvis
• a swollen or bloated abdomen
• appetite changes (e.g. not feeling like eating, feeling full quickly)
• changes in toilet habits (e.g. constipation, diarrhoea, passing urine more often, increased wind)
• indigestion and feeling sick (nausea)
• feeling very tired
• unexplained weight loss or weight gain
• changes to periods such as heavy or irregular bleeding, or vaginal bleeding after menopause
• pain when having sex.

If you have any of these symptoms and they are new for you, are severe or continue for more than two to three weeks, it is best to have a check-up.

Keep a note of how often the symptoms occur and make an appointment to see your general practitioner (GP). 

Ovarian Cancer Australia has produced a diary for recording symptoms. You can also use it to help talk about your health concerns with your doctor.

Risk factors

The causes of ovarian cancer are largely unknown, but factors that can increase the risk of developing ovarian cancer include:

• age – ovarian cancer is most common in women over 50 after periods have stopped, and the risk increases with age.
• genetic factors – up to 20% of serous ovarian cancers (the most common subtype) are linked to an inherited faulty gene, and a smaller proportion of other types are also related to genetic faults.
• family history – having close blood relatives (e.g. mother, sister) diagnosed with ovarian, uterine, breast or bowel cancers, or having Ashkenazi Jewish ancestry.
• endometriosis – this condition is caused by tissue from the lining of the uterus growing outside the uterus.
• reproductive history – women who have not had children, who have had assisted reproduction (e.g. in-vitro fertilisation or IVF), or who have had children after the age of 35 may be slightly more at risk.
• lifestyle factors – some types of ovarian cancer have been linked to smoking or carrying extra weight.
• hormonal factors – for example, early puberty or late menopause. Some studies suggest that menopause hormone therapy (MHT), previously called hormone replacement therapy (HRT), may increase the risk of ovarian cancer if taken for five years or more, but the risk is very low.

Some factors reduce the risk of developing ovarian cancer. These include having children before the age of 35, breastfeeding, using the combined oral contraceptive pill for several years, and having your fallopian tubes tied (tubal ligation) or removed.

Health professionals

Your GP will arrange the first tests to assess your symptoms. If these tests do not rule out cancer, you will usually be referred to a specialist called a gynaecological oncologist. The specialist will arrange further tests.

If ovarian cancer is diagnosed, the specialist will consider treatment options. Often these will be discussed with other health professionals at what is known as a multidisciplinary team (MDT) meeting.

During and after treatment, you will see a range of health professionals who specialise in different aspects of your care, including a gynaecological pathologist, radiologist, genetic counsellor and social worker, among others.

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