Ovarian cancer
The ovaries
The ovaries are part of the female reproductive system and contain the eggs (ova) which can make a new human life when fertilised. In women of childbearing age, a mature egg is released from one of the ovaries each month (ovulation) and travels down the fallopian tubes to the uterus (womb).
The ovaries are almond-shaped organs, each about 3 cm long and 1 cm thick. They are found inside the pelvic cavity, one on each side of the uterus (womb), and are very close to the end of the fallopian tubes.
What is ovarian cancer?
Ovarian cancer is a malignant tumour in one or both ovaries. There are 4 main types of ovarian cancer, named after the part of the ovary that is affected. Knowing exactly which type of cancer you have helps your doctor advise you on which treatment is best for you.
Epithelial ovarian cancer
This type of ovarian cancer arises in the epithelium: the outer cells covering the ovary. It is the most common type of ovarian cancer. Nine out of 10 ovarian cancers are epithelial.
Rarely, cancer develops in the fallopian tubes. This is very similar to epithelial ovarian cancer and it is treated in much the same way.
Germ cell and sex-cord stromal cell ovarian cancers
These 2 types of ovarian cancer are very uncommon. The germ cell cancers arise in the cells that mature into eggs, and usually only affect women under 30 years of age. Sex-cord stromal cell cancers arise in the cells which release the female hormones. These cancers can occur at any age.
These 2 types of ovarian cancers usually respond very well to treatment and are often curable. If these cancers affect only one ovary, it may still be possible for younger women to have children after treatment.
Borderline tumours
Borderline tumours are a group of epithelial tumours not as aggressive as other forms of ovarian cancer. Sometimes the words 'low malignant potential' are used to describe borderline tumours. The outlook for women with borderline tumours is generally good regardless of whether the disease is diagnosed early or late.
Who gets ovarian cancer?
About 9 out of 10 ovarian cancers occur in women over 40. Like most cancers, the risk of ovarian cancer increases with age.
What causes ovarian cancer?
The causes of ovarian cancer are not known. Some factors seem to put women at a higher risk of developing ovarian cancer.
- Ovarian cancer is more common in Caucasian (white) women who live in Western countries with a high standard of living.
- Women who have had no or few pregnancies appear to be more at risk of ovarian cancer. Women who have taken the contraceptive pill for a number of years seem to be at less risk. The exact reason is uncertain. It could be that ovarian cancer is more likely to develop when the ovaries do not have a 'rest' from ovulation (release of eggs) during a woman's lifetime.
- Some types of ovarian cancer may be linked with a family history of cancers of the ovary, bowel, breast and lining of the uterus. Between 5 and 10 per cent of ovarian cancers are caused by inheriting a damaged gene from a parent. If you are concerned about this, talk with your doctor.
Many women who develop ovarian cancer do not have these risk factors. At the same time many women who do have the risk factors do not develop ovarian cancer. Other risk factors may include a high fat diet, using talcum powder around the genital area and the mumps virus. The link between these factors and ovarian cancer has not been proved.
Last Reviewed: 20 April 2001
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