子宮癌-Cancer of the Uterus

What is the uterus?

The uterus (womb) is in the lower abdomen behind the bladder. The inside of the uterus is where a baby grows if you become pregnant. The inside lining of the uterus is called the endometrium. This builds up and is then is shed each month as a 'period' in women who have not yet gone through the menopause. The thick body of the uterus is called the myometrium and is made of specialised muscle tissue.

The lowest part of the uterus is called the cervix which pushes just into the top part of the vagina. At the top of the uterus are the right and left fallopian tubes which carry the eggs released from the ovaries to the inside of the uterus.

What is cancer?

Cancer is a disease of the cells in the body. The body is made up from millions of tiny cells. There are many different types of cell in the body, and there are many different types of cancer which arise from different types of cell. What all types of cancer have in common is that the cancer cells are abnormal and multiply 'out of control'.

A malignant tumour is a 'lump' or 'growth' of tissue made up from cancer cells which continue to multiply. Malignant tumours invade into nearby tissues and organs which can cause damage.

Malignant tumours may also spread to other parts of the body. This happens if some cells break off from the first (primary) tumour and are carried in the bloodstream or lymph channels to other parts of the body. These small groups of cells may then multiply to form 'secondary' tumours (metastases) in one or more parts of the body. These secondary tumours may then grow, invade and damage nearby tissues, and spread again.

Some cancers are more serious than others, some are more easily treated than others (particularly if diagnosed at an early stage), some have a better outlook (prognosis) than others.

So, cancer is not just one condition. In each case it is important to know exactly what type of cancer has developed, how large it has become, and whether it has spread. This will enable you to get reliable information on treatment options and outlook. See separate leaflet called 'What are Cancer and Tumours' for further details about cancer in general.

What is cancer of the uterus?

Most cancers of the uterus develop from cells in the endometrium (endometrial cancer). Cancer developing from muscle cells in the myometrium (uterine sarcomas) are rare and are not dealt with further in this leaflet. Cancer of the cervix is quite different to uterine cancer and is dealt with in a separate leaflet.

The rest of this leaflet deals only with endometrial cancer of the uterus.

Endometrial cancer

About 5000 women in the UK develop endometrial cancer each year. Most cases develop in women in their 50s and 60s. It rarely develops in women under the age of 50.

Type and grade of endometrial cancer
Most cases of endometrial cancer are called 'endometrioid adenocarcinomas'. These arise from cells which form the glandular tissue in the lining of the endometrium. A sample of cancer tissue can be looked at under the microscope. By looking at certain features of the cells the cancer can be 'graded'.

• Grade 1 (low grade) - the cells look reasonably similar to normal endometrial cells. The cancer cells are said to be 'well differentiated'. The cancer cells tend to grow and multiply quite slowly and are not so 'aggressive'.
• Grade 2 - is a middle grade.
• Grade 3 - the cells look very abnormal and are said to be 'poorly differentiated'. The cancer cells tend to grow and multiply quite quickly and are more 'aggressive'.

There are also some rarer types of endometrial cancer.

What causes endometrial cancer?

A cancerous tumour starts from one abnormal cell. The exact reason why a cell becomes cancerous is unclear. It is thought that something damages or alters certain genes in the cell. This makes the cell abnormal and multiply 'out of control'. (See separate leaflet called 'What Causes Cancer' for more details.)

There are 'risk factors' which are known to increase the risk of endometrial cancer developing. These include the following.

• Increased exposure to oestrogen. Oestrogen is the main female hormone. Before the menopause the changing level of oestrogen together with another hormone, progesterone, cause the endometrium to build up each month and then be shed as a period. It is thought that factors which lead to prolonged higher than usual levels of oestrogen, or increased levels of oestrogen not being 'balanced' by progesterone, may somehow increase the risk of endometrial cells becoming cancerous. These include:
  • If you have never had a baby (your uterus has never had a 'rest' from the cyclical rise of oestrogen every month). 醫(yī)學.全.在線.網.站.提供
  • If you are overweight or obese (fat cells make a certain amount of oestrogen).
  • If you take oestrogen-only HRT (hormone replacement therapy). Most women take 'combined HRT' which includes progestogen to balance the effect of oestrogen and causes much less of a risk of endometrial cancer than oestrogen-only HRT.
  • If you have certain rare oestrogen producing tumours.
  • If you have a late menopause (after the age of 52) or started periods at a young age.
• Endometrial hyperplasia. This is a benign (non cancerous) condition where the endometrium builds up more than usual. It can cause heavy periods, or irregular bleeding after the menopause. Most women with this condition do not develop cancer, but the risk is slightly increased.
• Tamoxifen. This is a drug which is used in the treatment of breast cancer. Although taking tamoxifen increases the risk of developing endometrial cancer, the benefits of taking it usually outweigh the risks.
• Diabetes and high blood pressure. The small increased risk with these two conditions may be related to the fact that many people with these conditions are overweight, and as mentioned, this increases the risk.
• Polycystic ovary syndrome. Possibly increases the risk. Again, the small increased risk may be related to the fact that many people with this condition are overweight.
• Diet. There are much fewer cases of endometrial cancer in certain eastern countries and dietary factors may be the reason. A western diet high in fat may be a contributing factor.
• Genetic factors. Most cases are not due to genetic or hereditary factors. In a small number of cases, a 'faulty' gene which can be inherited may trigger the disease.

What are the symptoms of endometrial cancer?

In most cases the first symptom to develop is abnormal vaginal bleeding such as:

• Vaginal bleeding in women past the menopause. This can range from 'spotting' to more heavy bleeds.
• Bleeding after having sex (post coital bleeding).
• Bleeding between normal periods (intermenstrual bleeding) in women who have not gone through the menopause.

An early symptom in some cases is pain during or after having sex, vaginal discharge, and pain in the lower abdomen.

All of the above symptoms can be caused by various other common conditions. But if you develop any of these symptoms, you should have it checked out by a doctor.

In time, if the cancer spreads to other parts of the body, various other symptoms can develop.

How is endometrial cancer diagnosed and assessed?

To confirm the diagnosis
A doctor will usually do a vaginal examination if you have symptoms which may possibly be due to endometrial cancer. He or she may feel an enlarged uterus. However, even if the examination is normal, if endometrial cancer is suspected you will usually need to have a further test to confirm the diagnosis, usually one of the following:

• Endometrial sampling. This is where a thin tube is passed into the uterus. By using gentle suction, small samples of the endometrium can often be obtained. This can be done without an anaesthetic. The sample (biopsy) is looked at under the microscope to check for abnormal cancerous cells.
• Hysteroscopy. This is where a doctor uses a hysteroscope which is a thin telescope that is pushed through the cervix into the uterus. The doctor can see the lining of the uterus and take samples (biopsies) of abnormal looking areas. This can be done without an anaesthetic.
• D and C (dilation and curettage). This test is done less commonly thesedays. It involves the cervix being dilated (widened), and then an instrument called a curette is inserted into the uterus to scrape samples of tissue from the endometrium to be looked at under the microscope. You need a general anaesthetic for a D and C.

You may also have an ultrasound scan of the uterus. An ultrasound scan is a safe and painless test which uses sound waves to create images of organs and structures inside your body. The probe of the scanner may be placed on your abdomen to scan the uterus. A small probe is also commonly placed inside the vagina to scan the uterus from this angle.

Assessing the extent and spread
If endometrial cancer is confirmed then further tests may be advised to assess if the cancer has spread. For example, a CT scan, an MRI scan, a chest x-ray, blood tests, an examination under anaesthetic of the uterus, bladder or rectum, or other tests. (There are separate leaflets which describe most of these tests in more detail.) This assessment is called 'staging' of the cancer. The aim of staging is to find out:

• How much the tumour has grown, and whether it has grown to other nearby structures such as the cervix, bladder or rectum.
• Whether the cancer has spread to local lymph glands (nodes).
• Whether the cancer has spread to other areas of the body (metastasised).

Finding out the stage of the cancer helps doctors to advise on the best treatment options. It also gives a reasonable indication of outlook (prognosis). See separate leaflet called 'Cancer Staging and Grading' for details.

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