Ovarian cancer

Tuesday 1 April, 2014

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On this page: The ovariesWhat is ovarian cancer?What types are there? | How common is it? | What are the symptoms? |  What are the risk factors? 

The ovaries

The ovaries are part of the female reproductive system. Other internal organs in the female reproductive system are the vagina, cervix, uterus (womb) and fallopian tubes.

The ovaries are two small, oval-shaped organs, each about 3 cm long and 1 cm thick in size. They are found in the lower part of the abdomen (the pelvic cavity). There is one ovary on each side of the uterus.

Each ovary has an outer covering made up of a layer of cells called the epithelium. Inside are germ cells, which will eventually mature into eggs (ova). The ovaries also release the female hormones oestrogen and progesterone from cells called sex-cord stromal cells.

An egg, called an ovum, is released from one of the ovaries each month (ovulation). The egg travels down the fallopian tube to the uterus. If the egg is fertilised by sperm, it can grow into a baby. If an egg is not fertilised by sperm, it disintegrates and – with the lining of the uterus – passes out of the vagina in the monthly period (menstruation).

As a woman gets older, the ovaries gradually produce less oestrogen and progesterone. The production of mature eggs also decreases and the woman’s periods become irregular and eventually stop. This is known as menopause, which usually happens between the ages of 45 and 55. After menopause, it is no longer possible to have a child by natural means.

A diagram of the female reproductive system

What is ovarian cancer?

Ovarian cancer is a malignant tumour in one or both ovaries. Some cases of ovarian cancer can form in the fallopian tube and spread to the ovary.

What types are there?

There are many types of ovarian cancer. The three most common types are:

  • Epithelial ovarian cancers: The majority of women with ovarian cancer have cancer that starts in the surface of the ovary (epithelium). Types of epithelial ovarian cancer include serous, clear cell, endometrioid and mucinous cancers.
  • Germ cell ovarian cancers: About 4% of women have these rare types of cancer, which start in the egg-producing cells. Germ cell cancers usually affect women aged around 35.
  • Sex-cord stromal cancers: Rare tumours may develop in the cells that produce female hormones. These cancers can occur at any age, and may produce extra hormones, such as oestrogen. They generally respond very well to treatment. 

Some women (usually younger women) are diagnosed with a borderline tumour. This is not considered to be cancer because, although it can spread, it does not invade other organs. For this reason borderline tumours are called low malignant potential tumours and usually have a good prognosis.

How common is it?

Each year, about 1400 Australian women are diagnosed with ovarian cancer. The average age at diagnosis is 64. It is the tenth most common cancer in women in Australia. Ovarian cancer is usually diagnosed in women over 50.

What are the symptoms?

Ovarian cancer may not cause any symptoms in its early stages, or it may cause only vague ones that are hard to recognise. If symptoms occur, they may include a swollen, bloated abdomen; pressure, discomfort or pain in the abdomen or pelvis; heartburn and nausea; changes in toilet habits (e.g. constipation, diarrhoea, frequent urination due to pressure, increased flatulence); tiredness and loss of appetite; unexplained weight loss or weight gain; changes in your menstrual pattern or postmenopausal bleeding; or pain during sex.

If these symptoms are new for you or continue over a four-week period, make an appointment with your general practitioner (GP). Having these symptoms does not necessarily mean you have cancer, but it is best to have a check-up.

Ovarian Cancer Australia has produced a symptom diary and a smartphone app, called KISS & Makeup, to help women record any symptoms and talk about their health concerns with their doctor.

What are the risk factors?

The causes of ovarian cancer are unknown, however risk factors include:

  • age: ovarian cancer is most common in women over 50 and in women who have stopped menstruating (have been through menopause), and the risk increases with age
  • child-bearing history: women who have not had children, were unable to have children, or had children over the age of 30 may be slightly more at risk
  • having endometriosis: a benign (non-cancerous) condition in which the tissue that lines the uterus (endometrium) is also found in other areas of the body
  • lifestyle factors: such as smoking tobacco, being overweight or eating a high fat diet
  • hormonal factors: including early puberty or late menopause, or using oestrogen-only hormone replacement therapy (HRT) for five years or more.

Most women with these risk factors don't develop ovarian cancer. Visit Cancer Australia for more information.

The importance of family history

About one in ten women diagnosed with ovarian cancer is believed to have inherited a fault in a gene that increased her risk of developing ovarian cancer. Not all women who inherit a faulty gene will develop ovarian cancer, but it increases a woman’s chance of developing ovarian cancer over the risk of the average woman.

Two main genetic conditions known to increase the risk of ovarian cancer include hereditary breast/ovarian cancer (fault in the BRCA1 and BRCA2 gene) and less commonly, hereditary non-polyposis colorectal cancer (HNPCC or Lynch syndrome, as it was formerly known).

If you have one or more of the risk factors listed below, you may like to talk with someone at a familial cancer clinic. Usually, these centres do not require a doctor’s referral and can be found in most major public hospitals. You can also find a list of familial cancer clinics on the Ovarian Cancer Australia website.

Protective factors

Some things may protect against ovarian cancer. These are called protective factors, and may include having children, breastfeeding, using the combined oral contraceptive pill for several years, having your fallopian tubes tied (tubal ligation), and the surgical removal of some female reproductive organs, such as the uterus or fallopian tubes. 

Inherited risk factors for ovarian cancer 

Any family member

  • who has had breast cancer before age 30
  • ovarian, fallopian tube or peritoneal cancer before age 50
  • who has had breast cancer in both breasts under the age of 50
  • who has had breast and ovarian cancer
  • who is a blood relative and has a known BRCA gene mutation
  • who has had breast cancer before age 60 or ovarian cancer at any age with Jewish ancestry
  • with male breast cancer

A personal history

  • of some types of ovarian, fallopian tube or peritoneal cancers, for women aged 70 or less with or without a history of breast cancer
  • Jewish ancestry

Two or more family members on the same side of the family (mother's or father's side)

  • diagnosed with breast and/or ovarian cancer

Reviewed by: A/Prof Martin K Oehler, Department of Gynaecological Oncology, Royal Adelaide Hospital, SA; Lucinda Hossack, Cancer Genetic Counsellor, Peter MacCallum Cancer Centre, VIC; Dr Kevin Palumbo, Radiation Oncologist, Adelaide Radiotherapy Centre, Flinders Private Hospital, SA; Nicole Wilton, Support Programs Manager, Ovarian Cancer Australia, VIC; Ilka Carapina, Consumer; and Cancer Council Queensland Helpline Operators.
Updated: 01 Apr, 2014