NHS A-Z Condition -

Uterine (Uterus) Cancer

Cancers of the uterus (womb) usually begin in the cells that make up the lining of the uterus (called the endometrium).

Cancers of the uterus are often called endometrial cancer because this term helps to distinguish them from other cancers that can affect the female reproductive system, such as cervical cancer or ovarian cancer.

The uterus and the endometrium

The uterus, commonly known as the womb, is the part of the female reproductive system where the baby is carried during pregnancy.

The uterus is lined by a layer of cells called the endometrium. The cells that make up the endometrium are regularly discarded during a woman’s monthly period, then replaced by new cells.

Types of endometrial cancer

There are two main types of endometrial cancer:

  • Type 1 endometrial cancer is a slow-growing cancer, thought to be linked to the female hormone oestrogen.
  • Type 2 endometrial cancer is a more aggressive, faster-growing form of cancer that does not appear to have any connection to oestrogen.

Type 1 endometrial cancer is the most common type, accounting for an estimated 80% of cases. Type 2 accounts for around 10% of cases.

As well as types 1 and 2 endometrial cancer, there are several rarer types of cancers of the uterus. For more information about these see Cancer Research UK: types of womb cancer.

How common is endometrial cancer?

Endometrial cancer is the most commonly occurring cancer of the female reproductive system. It is the fourth most common cancer that affects women, after breast cancer, lung cancer and cancer of the colon and rectum.

In 2007 in the UK, 7,536 new cases of endometrial cancer were diagnosed. Endometrial cancer is more common in women who have been through the menopause, and most cases of endometrial cancer (93%) were diagnosed in women aged over 50.

Obesity is a major risk factor for endometrial cancer. The number of cases of endometrial cancer is 10 times higher in Europe and north America than in the developing world. This can be explained by the corresponding high rates of obesity in Europe and north America.

Outlook

As with most types of cancer, the outlook depends largely on how far the cancer has advanced by the time it is diagnosed and the age at diagnosis. Eighty-five per cent of women diagnosed with early-stage type 1 endometrial cancer will be alive five years after diagnosis (the five-year survival rate).

Endometrial cancer can be treated by surgically removing the womb (hysterectomy). Radiotherapy and chemotherapy are also sometimes used after surgery to reduce the risk of the cancer returning.

Symptoms

Unusual vaginal bleeding

The main symptom of endometrial cancer is unusual bleeding from the vagina. Bleeding may start as light bleeding accompanied by a watery discharge, which may get heavier over time. Most women who are diagnosed with endometrial cancer have been through the menopause, and any vaginal bleeding will be unusual.

In women who haven’t been through the menopause, unusual vaginal bleeding may consist of:

  • periods that are heavier than usual
  • vaginal bleeding in between normal periods

Symptoms of advanced endometrial cancer

If endometrial cancer reaches a more advanced stage, it may cause additional symptoms. These include:

  • pain in the lower abdomen, back, legs or pelvis
  • unexplained weight loss

When to seek medical advice

If you have post-menopausal vaginal bleeding, or notice a change in the normal pattern of your period, visit your GP.

Only one in 10 cases of unusual vaginal bleeding after the menopause are caused by endometrial cancer, so it's unlikely that your symptoms will be caused by this condition.

However, if you have unusual vaginal bleeding, it is important to get the cause of your symptoms investigated because it may be the result of a number of other potentially serious health conditions, such as polyps or fibroids (non-cancerous growths that can develop inside the uterus). Also, other types of gynaecological cancer can cause unusual vaginal bleeding, particularly cervical cancer.

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Causes

How cancer begins

The body is made up of millions of different cells. Cancer happens when some of the cells multiply in an abnormal way. When cancer affects organs and solid tissues, it causes a growth called a tumour to form. Cancer can occur in any part of the body where the cells multiply abnormally.

How cancer spreads

Left untreated, cancer can quickly grow and spread from the uterus into other tissues in the pelvis or to other parts of the body. This usually happens through the lymphatic system.

The lymphatic system is a series of glands that are spread throughout the body and linked together in a similar way to the blood circulation system. If you have a cold or flu, the glands that come up in the neck are the lymph glands (also called lymph nodes). The lymph glands produce many of the cells that are needed by your immune system.

Once the cancer reaches your lymphatic system, it can spread to any other part of your body, including your bones, blood and organs.

Risk factors for endometrial cancer

It is not known exactly what causes endometrial cancer, but a number of important risk factors have been identified. They are:

Age

The risk of developing endometrial cancer increases with age. Most cases of endometrial cancer develop in women who are over the age of 50.

Oestrogen

The risk of developing endometrial cancer is linked to the exposure of the body to oestrogen. Oestrogen is one of the hormones that regulates the reproductive system in women.

  • Oestrogen stimulates the release of eggs from your ovaries and causes the cells of the womb lining (endometrium) to divide.
  • Progesterone gets the lining of your uterus (the endometrium) ready to receive the egg from the ovaries.

The levels of oestrogen and progesterone in your body are usually balanced with each other. If oestrogen isn’t kept in balance by progesterone, the level in the body can increase, this is called unopposed oestrogen.

After the menopause, the body stops producing progesterone. However, there are still small amounts of oestrogen being produced. This unopposed oestrogen causes the cells of the endometrium to divide, and this can increase the risk of endometrial cancer.

Hormone replacement therapy (HRT)

Because of the link between increased levels of unopposed oestrogen and endometrial cancer, oestrogen-only hormone replacement therapy (HRT) should only be given to women who have had their womb surgically removed (hysterectomy).

In all other cases, both oestrogen and progesterone (combination HRT) must be used in HRT in order to reduce the risk of endometrial cancer.

Being overweight or obese

One way to assess whether your weight is healthy is to calculate your body mass index (BMI). This is your weight in kilograms divided by your height in metres squared. In the UK, people with a BMI of 25 to 30 are overweight, and those with an index above 30 are obese.

Being overweight or obese is a major risk factor for endometrial cancer, as this increases the level of oestrogen in your body while also reducing the protective effects of progesterone.

Women who are overweight are three times more likely to develop endometrial cancer compared with women who are a healthy weight. Women who are very obese (with a BMI of more than 40) are six times more likely to develop endometrial cancer compared with women who are a healthy weight.

Diabetes

Women who have diabetes are twice as likely to develop endometrial cancer as women without the condition. Diabetes causes an increase in the amount of insulin in your body, which in turn can raise your oestrogen level.

Reproductive history

Women who have not had children are at a higher risk of endometrial cancer. This may be because the hormonal changes that occur during pregnancy have a protective effect on the womb (increased levels of progesterone and decreased levels of oestrogen). It may also be because hormonal changes associated with some forms of infertility (for example polycystic ovary syndrome) are associated with a failure of ovulation, causing a decrease in the level of progesterone and thus an increase in the level of unopposed oestrogen.

Tamoxifen

Women who are treated with tamoxifen (a hormone treatment for breast cancer) can be at an increased risk of developing endometrial cancer. However, this risk is outweighed by the benefits that tamoxifen provides in preventing breast cancer.

Polycystic ovarian syndrome (PCOS)

Women with polycystic ovarian syndrome (PCOS) are at a higher risk of developing endometrial cancer. Women with PCOS have multiple cysts in the ovary, and this can cause symptoms such as irregular or light periods, or no periods at all, problems getting pregnant, weight gain, acne and excessive hair growth (hirsutism).

Endometrial hyperplasia

Endometrial hyperplasia is when the lining of the womb becomes thicker. Women with the condition may be at increased risk of developing endometrial cancer.

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Diagnosis

If you have unusual vaginal bleeding, it is likely that your GP will carry out a physical examination of your vagina.

Your GP will ask about your symptoms, when they happen and how often. They'll also ask about your general health.

Transvaginal ultrasound (TVU)

If no obvious cause can be found for your symptoms, you may be referred for a transvaginal ultrasound (TVU).

TVU is a type of ultrasound scan that uses a small scanner, in the form of a probe. This is placed directly into the vagina to obtain a detailed picture of the inside of the uterus. The probe can feel a little uncomfortable, but shouldn't be painful.

The TVU checks whether there are any changes to the thickness of the lining of your uterus that could be caused by the presence of cancerous cells.

Biopsy

If the results of the TVU do detect changes in the thickness of the lining of the uterus, you will usually have a biopsy to confirm the diagnosis.

In a biopsy, a small sample of cells is taken from the lining of the womb (the endometrium). The sample is then checked at a laboratory for the presence of cancerous cells.

The biopsy can be carried out in a number of ways.

  • Aspiration biopsy: a small flexible tube is inserted into your vagina and up into your womb. This then sucks up a small sample of cells.
  • Hysteroscopy: this allows the doctor to look at the inside of the womb using a thin type of telescope called a hysteroscope. This is inserted through your vagina and into your womb. It enables the doctor to look at the lining of the womb and take a sample from it.

For most women, the tests can be done at the outpatient clinic, but some may find the tests painful and need to be admitted for a general anaesthetic.

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Tests if you're diagnosed with endometrial cancer

If you're diagnosed with endometrial cancer, you may have further tests that can help to determine the stage of the cancer. Staging the cancer will allow the doctors to work out how large the cancer is, whether or not it has spread and the best treatment options for you.

These further tests may include:

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Prevention

Healthy weight, diet and exercise

The most effective way to prevent endometrial cancer is to maintain a healthy weight.

The best way to avoid becoming overweight or obese is to eat healthily and exercise regularly.

A low-fat, high-fibre diet is recommended, including wholegrains and at least five portions a day of fresh fruit and vegetables.

For most people, at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity (i.e. cycling or fast walking) every week, at least five times a week, is recommended.

If you haven't exercised before, or haven't done it for some time, see your GP for a health check-up before you start a new exercise programme.

Soya

Some research has suggested that a diet high in soya may possibly help to prevent endometrial cancer. Soya contains isoflavens, which may help to protect the lining of the womb. Foods that are high in soya include soya beans and tofu. However, further research into this area has been recommended.

Contraception

Research has shown that long-term use of combination oral contraception (the contraceptive pill that contains both oestrogen and a synthetic version of progesterone) can lower the risk of endometrial cancer.

Other types of contraception such as contraceptive implants and the intrauterine system (IUS) work by releasing progestogen (a synthetic version of progesterone). These may also reduce the risk of endometrial cancer.

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