Causes and risk factors of womb cancer
Find out more about factors that may increase the risk of developing womb cancer.
Womb cancer risk factors
Most womb cancers start in glandular cells found in the lining of the womb (the endometrium). They are called endometrial cancers. There are different types of endometrial cancers.
There are some things that can increase the risk of developing womb cancer. These are called risk factors. Womb cancer risk is often linked to hormone levels changing over time. But this is not always the case. Sometimes the cause is not clear.
Having a risk factor does not mean you will get womb cancer. And not having a risk factor does not mean that you will not get womb cancer.
If you are worried about womb cancer and would like to talk to someone, we're here. You can:
- call the Macmillan Support Line on 0808 808 00 00
- use our online form to email us and we will respond within 2 working days
- chat to our specialists online.
Age
The risk of womb cancer can be related to age.
Womb cancer is rare in people aged under 45 and becomes more common after the age of 55. The number of people diagnosed with womb cancer then increases until the age of 79. More than a quarter of people (25%) diagnosed with womb cancer are aged between 75 and 79. After the age of 79 the number of people being diagnosed goes down. This is due to natural hormone changes.
Hormonal factors
Womb cancer is sometimes linked to higher levels of the hormone oestrogen across a person's lifetime. Higher levels of oestrogen may be due to having a lot of periods. For example:
- starting periods early (before the age of 12)
- a late menopause (after the age of 55)
- irregular periods.
It can also be due to having less of the hormone progesterone. Progesterone balances the effect of oestrogen. Before the menopause, the ovaries produce both hormones. After the menopause, the ovaries stop producing these hormones. But some oestrogen is still produced in body fat and by the adrenal glands.
This means oestrogen levels can be higher due to:
- hormone replacement therapy (HRT), particularly oestrogen-only HRT
- not ever having been pregnant as oestrogen levels are low and progesterone is high during a pregnancy
- a natural hormone imbalance.
Tamoxifen
Tamoxifen is a hormonal therapy used to treat breast cancer, or to prevent breast cancer coming back. Taking tamoxifen can increase the risk of developing womb cancer.
The benefits of taking tamoxifen usually outweigh the risk of womb cancer. Always tell your doctor if you are taking tamoxifen and are having irregular or unexpected bleeding or discharge from the vagina. They may arrange tests to check for changes to the lining of the womb.
Weight and physical activity
At least 1 in 3 womb cancers (33%) may be caused by being very overweight (obese). This may be linked to body fat being the main source of oestrogen after the menopause.
Researchers think that being more physically active may reduce the risk of womb cancer.
Genetic factors (family history)
A small number of womb cancers (5-10%) are caused by gene changes that are passed on in a family (inherited).
There are some genetic conditions that can increase the risk of womb cancer.
Lynch syndrome
Lynch syndrome is a condition that can increase the risk of bowel, ovarian and womb cancer. Lynch syndrome means there is up to a 6 in 10 risk (60%) of developing womb cancer over your lifetime.
Sometimes doctors might suggest having risk-reducing surgery to remove the womb (hysterectomy).
Cowden syndrome
Cowden syndrome is a rare genetic condition. It increases the risk of non-cancerous tumours and some cancers such as breast and ovarian cancer. This also includes womb cancer, but the increase in risk is small.
Related pages
Other medical conditions
Some other medical conditions may cause an increased risk of pre-cancerous changes or cancer in the womb.
Thickening of the womb lining
Thickening of the lining of the womb is called endometrial hyperplasia. It can increase the risk of womb cancer, especially if cells in the womb lining have abnormal changes (pre-cancerous changes). Symptoms include:
- heavy periods
- bleeding between periods
- bleeding after the menopause.
Endometrial hyperplasia can be monitored for abnormal cells.
Always talk to your GP if you have any abnormal vaginal bleeding.
Diabetes
Diabetes can affect oestrogen levels and increase the risk of womb cancer. There may also be a separate link between womb cancer and how well your body uses insulin. This is the hormone that regulates blood sugar. If you have diabetes, your body either does not make enough insulin or cannot use it properly.
Polycystic ovary syndrome (PCOS)
PCOS is a hormone imbalance which can cause irregular, or no, periods. It can also cause cysts to grow on the ovaries. PCOS can lead to an imbalance in oestrogen and progesterone which can increase the risk of womb cancer. PCOS is linked to:
- weight gain
- problems with insulin levels or diabetes.
Rare ovarian cancers
Some rare types of ovarian cancer called granulosa tumours and theca cell tumours can produce oestrogen. This increases the risk of pre-cancerous changes in the womb and cause womb cancer. This is rare.
Chemicals
Doctors are studying whether the chemicals found in some hair straightening products might increase the risk of womb cancer. Further research is needed to confirm this and to rule out other causes.
About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
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References
Below is a sample of the sources used in our womb cancer information. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk
Oaknin, A. et al. Endometrial cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Annals of Oncology, Volume 33, Issue 9, 860 - 877
https://www.esmo.org/guidelines/guidelines-by-topic/esmo-clinical-practice-guidelines-gynaecological-cancers/endometrial-cancer (accessed January 2024).Berek JS, Matias-Guiu X, Creutzberg C, et al. FIGO staging of endometrial cancer: 2023. Int J Gynecol Obstet. 2023; 162: 383-394. doi:10.1002/ijgo.14923 (accessed January 2024).
Suspected cancer: recognition and referral. NICE guideline [NG12] Published: 23 June 2015 Last updated: 02 October 2023 Overview | Suspected cancer: recognition and referral | Guidance | NICE (accessed January 2024).
Miss Eva Myriokefalitaki
Reviewer
Consultant Gynaecological Oncology Surgeon
Date reviewed
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