Endometrial cancer

• Abnormal bleeding – after sex, between your periods or any bleeding after menopause – this is the most common symptom.
• Abnormal vaginal discharge.
• Unexplained weight-loss.
• Pelvic pain.
• Abdominal pain or swelling.
• Problems passing urine or bowel motions.

The exact cause of endometrial cancer is unknown, but increased exposure to the hormone oestrogen is linked to most endometrial cancers. Oestrogen helps stimulate growth of endometrial cells and is normally balanced by progesterone (which reduces their growth). In the absence of progesterone, or when too much oestrogen is produced, abnormal growth of endometrial cells occurs, which can then lead to cancer.

Image credit: 123rf

The greatest risk factors for endometrial cancer are age and obesity.

• Endometrial cancer is much more common in post-menopausal women, with the average age at diagnosis being 60–65 years.
• Being overweight or obese increases your risk of developing endometrial cancer, with >50% of endometrial cancers being attributed to obesity. See the FAQ section below for further information.
• Having endometrial hyperplasia (pre-cancerous condition, where the lining of the uterus is thickened) also increases your risk.

Other risk factors include:

• Polycystic ovarian syndrome (PCOS) – women with PCOS often have irregular periods and are more likely to become overweight and develop diabetes.
• Type 2 diabetes, hypertension, raised cholesterol.
• Some hormone therapies used for breast cancer therapy such as Tamoxifen can also increase the risk of endometrial cancer.
  • If you are prescribed tamoxifen your doctor will discuss this with you and also talk about how this risk can be minimised.
  • It is important to remember that the improvement in survival from breast cancer is a big benefit, compared to the small increase in risk of endometrial cancer.
• Hormone producing tumours – this is a rare cause of endometrial cancer.
• Genetic problems such as Lynch syndrome. These are relatively rare (around 5%) but women with Lynch syndrome often develop endometrial cancer before menopause.
• A family history of endometrial, ovarian or colorectal cancer.

as Lynch syndrome. These are relatively rare (around 5%) but women with Lynch syndrome often develop endometrial cancer before menopause.

FAQs about risk factors

Why is endometrial cancer more common after menopause?

The increased risk of endometrial cancer after menopause is because the lining of the uterus is no longer shed as part of a woman’s period each month.

Having regular periods protects against endometrial cancer because it prevents build-up of the cells lining the uterus. During a normal monthly cycle, endometrial cells lining the uterus grow and mature in response to the hormones oestrogen and progesterone, preparing your womb for implantation and pregnancy. If implantation doesn't occur, these cells are shed and you have your period. 

After menopause, oestrogen is mostly made in the body by fatty tissue, and your ovaries are no longer producing hormone-cycles to regulate the lining of the uterus. The enzymes that produce oestrogen increase in quantity and activity with age, increasing the production of oestrogen. This increases the risk of endometrial cancer in post-menopausal women.

Why does being obese increase my risk of endometrial cancer? 

It's been estimated that 40% of endometrial cancers are due to obesity.

If you have a BMI of 35, your chance of getting endometrial cancer is 4.7 times the chance of a woman with a BMI of 25. The outcomes for endometrial cancer are also worse for obese women compared to women who are in a healthy weight-range.

Women who are overweight are less likely to have regular periods, and therefore more likely to have an abnormal build-up of endometrial cells (before menopause).

Although oestrogen is usually produced in the ovaries, fat cells also make oestrogen, so women who are overweight generally produce more oestrogen. This stimulates the lining of the uterus to grow, and increases the risk of endometrial cancer. Obesity also creates a chronic inflammatory state in the body, which contributes to increased cancer risk.  

How does the pill reduce my risk of endometrial cancer?

The combined contraceptive pill (and hormone replacement therapy) include both oestrogen and progesterone. Progesterone slows cell growth, balancing the stimulating effect of oestrogen, which helps prevent abnormal cell growth and the development of endometrial cancer.

Endometrial cancer is less common in women who:

• have regular periods
• are on the combined contraceptive pill – your risk decreases by 24% after 5 years of use
• use progesterone-containing intrauterine contraceptive devices
• have had at least 1 baby
• breastfed for more than 18 months
• exercise regularly
• have a healthy diet
• maintain a healthy weight
• don't smoke.

The main way of diagnosing endometrial cancer is by taking a sample of the lining of the uterus and there are a couple of ways to do this. Sometimes an ultrasound will also be recommended. 

Pipelle biopsy

A pipelle biopsy [PDF, 199 KB] is a simple procedure. It involves a speculum examination (similar to a cervical smear) where the plastic speculum is placed in your vagina, and a thin plastic straw (pipelle) is passed through your cervix and into your uterus. A sample of the cells from the lining of your uterus is taken and sent to a lab where they are checked for abnormalities. No anaesthetic is needed for the procedure and it can be done by your healthcare provider or Sexual Wellbeing Aotearoa.

Occasionally a cervical sample test might find abnormal cells that suggest an endometrial cancer, however, a regular smear test cannot be used to reliably diagnose endometrial cancer. 

Ultrasound

An ultrasound is a good way of looking at the thickness of the lining of your uterus. After menopause, the lining of your uterus should be quite thin. If the lining of the uterus is less than 4mm then the chance of a cancer of the endometrium is very low. If you’re still having periods, the measurement of the lining is less reliable as it changes a lot during your cycle.

Hysteroscopy, dilatation and curettage (Hysteroscopy, D&C)

This procedure involves removal of a small amount of tissue from inside your uterus. It’s usually done if a pipelle biopsy isn’t possible, or if an ultrasound shows that the lining of the uterus is thicker than it should be. It usually requires you to have a light anaesthetic. A thin camera is then passed through the cervix into the uterus and the lining can be assessed. A sample of the lining or any polyps can be taken and sent to the lab.

Endometrial hyperplasia is where the lining of the uterus has grown abnormally and has potential to become cancer. This can be diagnosed from a pipelle biopsy or a D&C.

Some types of endometrial hyperplasia can be managed with progesterone, either in tablet form or using a Mirena (contraceptive intra-uterine device which releases progesterone). This reduces the chance of it progressing to endometrial cancer.

Other types of endometrial hyperplasia already have changes that are suspicious for cancer, so they're managed more similarly to endometrial cancer with surgery.

Treatment options for endometrial cancer include surgery, radiation therapy and chemotherapy. This will depend on the type of cancer it is, how quickly it's growing and if it has spread to other areas in your body.

Surgery

Most women with endometrial cancer will require surgery. Because the cancer usually spreads to the fallopian tubes and the ovaries first, the operation will involve the removal of your uterus and cervix (a total hysterectomy) and both tubes and ovaries (a bilateral salpingo-oophrectomy). Sometimes lymph nodes may need to be removed as well.

Radiotherapy

Radiation treatment is often used for more advanced or high-risk cases. This type of treatment is called adjuvant therapy which means additional therapy. Occasionally the radiotherapy is given before surgery so that the surgery is more likely to remove all of the tumour, but usually it’s used after surgery. Treatment is usually delivered into your vagina (which has less side-effects), but sometimes external radiation is recommended instead.

Chemotherapy

Chemotherapy is used as adjuvant therapy, but only for some types of cancer or in more advanced cases of cancer. Chemotherapy does often cause a number of side-effects such as hair loss, gastrointestinal problems and a lowering (or suppressing) of your immune system.

Hormonal treatment

If the cancer is very early and a woman wishes to have children, then the cancer can be treated with hormone therapy until she has finished having babies.

Occasionally hormone treatment may be used when surgery is too risky. A common reason for this is because the patient has other medical conditions or is severely obese, which makes the operation or the anaesthetic too dangerous. 

Endometrial cancer is associated with obesity, high blood pressure and diabetes. You can lower your chance of developing endometrial cancer by:

• Maintaining a good weight: A normal BMI is between 20 and 25. A BMI of over 30 is considered to be obese. Check your BMI with our BMI calculator. If you are really concerned about your weight and are very motivated to lose weight, you could also consider surgical options for weight loss.  
• Exercising regularly: You do not need to become a marathon runner but you can make small but important changes every day. Try doing things such as walking up the stairs instead of using the lift or walking or using a bicycle instead of jumping in the car. Read more about abut how to get started. 
• Eating a healthy, balanced diet: One that's high in vegetables and low in sugary, processed foods. Read more about healthy eating.
• Quitting smoking.

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