For most women with a family history of ovarian cancer, their risk will not be much higher than that of the general public (only around one in seventy women get ovarian cancer in their lifetime).
If you have a first-degree relative with ovarian cancer, (mother, sister or daughter), then your risk may be increased to around one in twenty. This is considered to be moderately increased risk. However, in some circumstances women with just one relative with ovarian cancer can be at very high risk (up to 1 in 2) of getting the disease themselves. This article explains what to look for in your family history.
If there are two or more relatives with ovarian cancer in your family, or one relative with ovarian cancer and one with breast cancer before the age of 50 years (or two relatives with breast cancer before the age of 60 years), then you may be at high risk of developing ovarian cancer. In certain cases, this risk could be as high as one in two by the age of 70 years.
If there is Ashkenazi (Central and Eastern European) Jewish ancestry on the same side of your family as a relative with ovarian cancer, then there could be an inherited predisposition to cancer in your family, even if only one relative has had the disease.
A family history of ovarian cancer could raise the possibility of a BRCA1 or BRCA2 gene alteration being present in the family. This is especially true if there is also a history of breast cancer or Ashkenazi Jewish ancestry on the same side of the family. More recently, it has also become apparent that around 1 in 10 women with the most common type of ovarian cancer (high grade serous cancer) carry one of these gene alterations.
It’s important to remember that an inherited predisposition to cancer, such as a BRCA gene alteration, can be passed down from your father’s side of the family as easily as your mother’s. Therefore you shouldn’t ignore a family history of cancer on your father’s side of the family.
If there is a strong family history of bowel and/or endometrial (womb-lining) cancer, then this should raise the possibility of a different inherited predisposition to cancer, known as Lynch Syndrome. Women with this condition also have an increased risk of ovarian cancer.
We know that the following can affect the risk, but none of these factors influence risk as much as a strong family history of the disease:
- Using the combined oral contraceptive pill halves your risk if you have used it for 5 years or more.
- Using other types of hormonal contraception (minipill, injectable contraception, contraceptive implants) can reduce your risk of ovarian cancer.
- Breastfeeding reduces the risk of ovarian cancer.
- The more children you have had, the lower your risk of ovarian cancer.
- Having a sterilisation operation (clips placed on the Fallopian tubes) reduces the risk of ovarian cancer.
- Taking hormone replacement therapy (HRT), having endometriosis, being overweight or smoking all slightly increase the risk of ovarian cancer.
- Using talc on the genital area may cause a small increase in risk.
- Exposure to asbestos may cause a small increase in risk.
- Some fertility treatments may cause a slight increase in risk, but this risk is small and probably confined to women who do not achieve a successful pregnancy following fertility treatment. Also, fertility treatment probably only increases the risk of borderline ovarian tumours which tend to have a very good prognosis.
- Recent evidence has suggested that premenopausal women with polycystic ovarian syndrome (which is different to just having polycystic ovaries) may have a slightly higher risk of ovarian cancer.
You should try to find out as much as you can about your relatives with cancer. If possible, find out how old they were when they were diagnosed with cancer and what type of cancer they had. The age someone is when they develop certain types of cancer can influence how likely it is the cancer was inherited. If your relative is no longer alive, try to get hold of a copy of their death certificate confirming the type of cancer they had. Your local town hall can help you with this. Once you’ve got as much information as you can, see your GP and ask them if you need to be referred to your local Clinical Genetics service for advice about gene testing.
This situation requires expert advice form a gynaecologist with a special interest in this area of medicine. Most gynaecological oncologists (gynaecologists specialising in the treatment of cancer) have experience of advising women with an increased risk of ovarian cancer.
Gynaecologists working with Clinical Genetics
In many cases, it is appropriate to offer such women a ‘keyhole’ operation to remove the ovaries and fallopian tubes to prevent the development of cancer. However, this usually needs to be done before the menopause and therefore women may need to take hormone replacement therapy (which is safe in this situation) to prevent unpleasant symptoms and reduce their future risk of osteoporosis. The operation can also reduce their risk of breast cancer substantially. Clinical Genetics teams usually work closely with expert gynaecologists and can refer you to them. Alternatively, your GP can refer you to a local gynaecologist with a special interest in this area.
The time of a woman’s life when her ovaries stop releasing an egg (ovum) on a monthly cycle, and her periods ceaseFull medical glossary