About the ovaries and
ovarian cancer
This information is an extract from the booklet Understanding
cancer of the ovary. You may find the full booklet helpful.
We can send you a free copy – see page 8.
Contents
• The ovaries
• Risk factors and causes
• Symptoms
The ovaries
The ovaries are two small, oval-shaped organs in the pelvis
(the area between the hips in the lower part of the tummy).
They are part of the female reproductive system, which is
made up of the ovaries, fallopian tubes, womb (uterus),
cervix and vagina.
Each month, in women of childbearing age, one of the
ovaries produces an egg (ovulation). The egg passes down
the fallopian tube to the womb. If the egg isn’t fertilised by a
sperm, it passes out of the womb as part of the monthly period.
The ovaries and surrounding structures
Fallopian
tube
Bladder
Cervical
canal
Vagina
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Ovary
Womb
Cervix
Urethra
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About the ovaries and ovarian cancer
The ovaries also produce the female hormones oestrogen and
progesterone. As a woman gets nearer to the menopause,
the ovaries make less of these hormones and your periods
gradually stop.
Organs close to the ovaries
There are several organs close to the ovaries. These include:
•the bladder
•the ureters, which drain urine from the kidneys to the bladder
•the back passage (rectum – see the diagram on page 3)
•part of the bowel (see the diagram on page 3)
•the peritoneum – a membrane that surrounds and keeps
the pelvic and abdominal organs in place (see the diagram
on page 3)
•the omentum – a fatty membrane made up of a fold of the
peritoneum at the front of the abdomen, which extends from
the lower curve of the stomach and covers the front of the
bowel (see the diagram on page 3)
•groups of lymph nodes
•the womb.
Organs close to the ovaries
Kidney
Ureter
Omentum
Lymph
node
Lymphatic
vessel
Rectum
Page 2 of 8
Fallopian
tube
Ovary
Bladder
Womb
Urethra
Vagina
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About the ovaries and ovarian cancer
Side view of the body
Liver
Peritoneum
Stomach
Omentum
Spine
Peritoneal
space
Bowel
Womb
Ovary
Bladder
Rectum
(back passage)
Risk factors and causes
About 7,000 women in the UK are diagnosed with ovarian
cancer every year.
We don’t know exactly what causes it. But, we know some of
the risk factors that may increase the chances of developing
ovarian cancer.
Having a particular risk factor doesn’t mean you will definitely
get cancer – just as not having any risk factors doesn’t mean
you won’t. Usually, cancer is the result of the combination
of several risk factors.
Here are some risk factors that may affect a woman’s chance
of developing ovarian cancer.
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Page 3 of 8
About the ovaries and ovarian cancer
Age
Age is a common risk factor for many cancers. The risk of
developing ovarian cancer is very low in young women and
increases as women get older. More than 8 out of 10 (80%)
of ovarian cancers occur in women over the age of 50. It is
rare in women under 30.
Hormonal factors
Doctors think the number of times a woman releases an egg
(ovulates) may be linked to ovarian cancer risk. Women who
don’t have children have a higher risk of developing ovarian
cancer.
Certain factors that reduce ovulation (when one of the ovaries
produces an egg) may help lower the risk of ovarian cancer,
for example, taking the contraceptive pill, having children and
breastfeeding.
We have more detailed information about factors that help
lower risk in our leaflet Are you worried about ovarian
cancer?
Hormone replacement therapy (HRT)
HRT increases the risk of developing ovarian cancer but only
slightly. About 1% of cases may be linked with taking HRT.
The risk only slightly decreases after stopping taking it.
Medical conditions
Previous breast cancer
Women who have breast cancer may have an increased risk
of developing ovarian cancer. This may be because these
cancers have some risk factors in common.
Endometriosis
Endometriosis is a condition where the lining of the womb
grows outside the womb. Having endometriosis slightly
increases the risk of developing ovarian cancer.
Diabetes
Women with diabetes may have a slightly higher risk of
developing ovarian cancer.
Page 4 of 8
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About the ovaries and ovarian cancer
Lifestyle factors
Weight
Some studies have found a link between being very overweight
(obese) and an increased risk of developing ovarian cancer.
Taller women may also have a higher risk of ovarian cancer.
Smoking
Smoking cigarettes may slightly increase the risk of developing
mucinous ovarian cancer.
Our booklet Giving up smoking has more
information and tips to help you quit.
Family history
If your mother or sister has had ovarian cancer, this slightly
increases your risk of developing it. But the chance of you
getting ovarian cancer is still low.
Our leaflet Are you worried about ovarian cancer?
has more information.
Women who have two or more close relatives who’ve had
ovarian cancer or certain other types of cancer may be at
a higher risk (see below).
Inherited risk
A small number of ovarian cancers, up to about 10–15%,
are thought to be due to an inherited change (alteration) in a
gene. The altered genes that increase the risk of developing
ovarian cancer and also breast cancer are BRCA1 and BRCA2.
If a family has an altered gene, usually several relatives on the
same side of the family have had ovarian cancer or related
cancers, such as breast, bowel or womb cancer. They may
have also have been diagnosed at a particularly young age.
Doctors are mostly interested in the history of cancer in your
close relatives (first-degree and second-degree relatives).
First‑degree relatives are your parents, brothers, sisters
and children. Second‑degree relatives are your grandparents,
grandchildren, aunts, uncles, nieces and nephews.
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Page 5 of 8
About the ovaries and ovarian cancer
If any of the following are present on one side of your family,
it’s possible there may be an inherited altered gene that
increases the risk of ovarian cancer:
•two or more close relatives diagnosed with ovarian cancer,
including at least one first-degree relative
•a first-degree relative diagnosed with ovarian cancer,
and a close relative under the age of 50 diagnosed with
breast cancer
•a first-degree relative diagnosed with ovarian cancer and
a male relative diagnosed with breast cancer
•a first-degree relative diagnosed with both ovarian and
breast cancer
•a first-degree relative with ovarian cancer, and two close
relatives diagnosed with breast cancer before they reached
an average age of 60
•one close relative with ovarian cancer and three or more
relatives with colon (bowel) and/or womb (endometrial)
cancers.
If your GP agrees that you may be at increased risk because
of your family history, they will refer you to a clinical genetics
service or a family cancer clinic.
Online risk assessment
We have an online tool you can use to assess your risk of
developing breast or ovarian cancer. OPERA (Online Personal
Education and Risk Assessment) asks you about ten questions
before giving you personalised information and support about
your inherited cancer risk. Visit macmillan.org.uk/opera
to use the tool.
‘I’ve talked to my daughters. They want
to be tested because I think that
forewarned is forearmed. Had I known
that I carried the gene, what the
symptoms were and what to look out
for, I think I’d have been a lot more
determined with my doctors.’
Karen
Page 6 of 8
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About the ovaries and ovarian cancer
Symptoms
The symptoms of ovarian cancer can be very similar to
symptoms of other more common conditions. To try to
make sure women are diagnosed as early as possible, NICE
(National Institute for Health and Care Excellence) give the
following guidance on symptoms.
GPs should offer ovarian cancer tests to women who have
symptoms of bloating and any of the other symptoms below
if they happen more than 12 times a month or continue for
three weeks:
•a long-lasting bloated feeling in your tummy (having
a swollen tummy)
•feeling full quickly and/or loss of appetite
•pain or discomfort in the lower tummy area and/or back
•needing to pass urine more often or more urgently
(feeling like you can’t hold on).
Women over 50 who develop symptoms similar to irritable
bowel syndrome (IBS) should also see their GP for ovarian
cancer tests. IBS symptoms include bloating and changes in
bowel habit. It is unusual for women over 50 to develop IBS
for the first time.
All these symptoms can be caused by other conditions but it’s
very important to get them checked by your GP.
Other possible symptoms of ovarian cancer may include:
•changes in bowel habits (diarrhoea or constipation)
•pain during sex
•weight gain or weight loss
•unexplained or extreme tiredness.
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About the ovaries and ovarian cancer
More information and support
More than one in three of us will get cancer. For most of us
it will be the toughest fight we ever face. And the feelings
of isolation and loneliness that so many people experience
make it even harder. But you don’t have to go through it alone.
The Macmillan team is with you every step of the way.
To order a copy of Understanding cancer of the ovary, or
any other cancer information, visit be.macmillan.org.uk
or call 0808 808 00 00.
We make every effort to ensure that the information we provide is accurate and up to
date but it should not be relied upon as a substitute for specialist professional advice
tailored to your situation. So far as is permitted by law, Macmillan does not accept
liability in relation to the use of any information contained in this publication, or thirdparty information or websites included or referred to in it. © Macmillan Cancer Support
2013. Registered charity in England and Wales (261017), Scotland (SC039907) and the
Isle of Man (604). Registered office 89 Albert Embankment, London, SE1 7UQ
REVISED IN MAY 2015
Planned review in 2017
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