Endometrial Cancer Risk Factors: Who is Most at Risk? – Thomson Medical

Endometrial cancer is most often diagnosed after menopause, and that’s where most people’s picture of it stops. But age isn’t the whole story. The risk is due to factors such as long-term exposure to oestrogen, conditions like PCOS and diabetes, never having been pregnant, and, in a smaller number of cases, an inherited condition such as Lynch syndrome. Some of these affect younger women too.

Here are the risk factors for endometrial cancer, which of them can be modified, and the symptoms that are worth seeing a doctor.

What is endometrial cancer?

Endometrial cancer is a type of cancer that develops in the endometrium, or inner lining of the uterus (womb), which is the most common type of uterine cancer. Endometrial cancer develops when healthy cells in the lining of the womb undergo DNA changes that trigger them to divide at an abnormal rate. 

Instead of dying naturally, these abnormal cells accumulate and clump together to form a tumour. If left untreated, these cancer cells may eventually invade surrounding healthy tissue or spread to other parts of the body.

Endometrial cancer risk factors

While the exact cause of endometrial cancer is not fully understood, it could develop due to a combination of hormonal, genetic, and lifestyle factors. Knowing these endometrial cancer risk factors could help you be more aware of your personal risk.

Older age

The risk of developing endometrial cancer may increase as you get older, especially if you are over 50 and have gone through menopause. 

This increased risk is linked to longer exposure to oestrogen (the hormone that helps the womb lining grow and thicken) and age‑related changes in the uterine lining, especially when oestrogen is not adequately balanced by progesterone (the hormone that supports menstruation and early stages of pregnancy).

After menopause, your ovaries largely stop producing both oestrogen and progesterone. However, your body could still make small amounts of oestrogen from other parts of your body. 

When this oestrogen is not balanced by progesterone, it may create a condition known as “unopposed oestrogen”, where oestrogen is not balanced by progesterone, which could overstimulate the uterine lining and increase the risk of endometrial cancer.

Early menarche

Early menarche is a condition where a girl experiences her first menstrual period at an unusually young age, typically before the age of 12. This may result in longer-term exposure to oestrogen, which increases the risk of endometrial cancer.

Late menopause

Late menopause could happen because your ovaries are still producing oestrogen. Therefore, your body will also have more years of exposure to oestrogen. This means the lining of the womb is stimulated for a longer time, which may increase the risk of endometrial cancer, especially if progesterone is not enough to balance oestrogen’s effect.

Obesity

Obesity is a major risk factor for endometrial cancer because fat tissue contains an enzyme that changes other hormones into oestrogen. This could lead to raised oestrogen levels, resulting in unopposed oestrogen when there is insufficient progesterone to balance its effects.

Additionally, obesity often causes insulin resistance, meaning the pancreas has to produce more insulin than it normally would. This extra insulin helps cancer cells to grow and reduces the proteins that usually attach to oestrogen, leaving more oestrogen circulating in your blood. 

Excess fat also causes a constant, low-level inflammation that may damage DNA and weaken your immune system's ability to destroy mutated cells.

Diabetes

Diabetes is associated with a higher risk of endometrial cancer, partly because it often involves insulin resistance and chronically high blood sugar. They are linked to hormonal and metabolic changes that promote abnormal growth in the uterine lining.

When diabetes occurs together with obesity, these metabolic changes could compound and further raise risk.

Polycystic ovary syndrome (PCOS)

PCOS significantly elevates the risk of developing endometrial cancer, primarily due to chronic hormonal imbalances that affect the uterine lining and irregular menstrual cycle.

Without regular ovulation, your body does not produce progesterone in a normal cyclical pattern. Therefore, the womb lining may be exposed to oestrogen for longer periods without adequate progesterone balance, increasing endometrial cancer risk. 

Unhealthy lifestyle

An unhealthy lifestyle could increase your risk of endometrial cancer by contributing to metabolic problems such as high blood sugar, insulin resistance, and chronic inflammation. These changes are associated with hormonal and cellular environments that make abnormal growth in the womb lining more likely. 

Nulliparity

Nulliparity (never having been pregnant) may be a risk factor for endometrial cancer mainly because of its impact on your hormonal exposure. This is because pregnancy gives the lining of the womb a break from oestrogen by producing high levels of progesterone.

If you have never been pregnant, your body does not experience these long periods of high progesterone and paused menstrual cycles. Over time, this usually means more menstrual cycles and relatively more oestrogen exposure compared with women who have had pregnancies.

Genetic conditions

Inherited genetic mutations, such as Lynch syndrome, could elevate the risk of developing endometrial cancer. 

It is caused by inherited mutations in DNA mismatch repair genes that normally fix errors made during cell division. When these repair systems are faulty, DNA damage may build up more quickly and lead to uncontrolled cell growth and tumour formation.

Medical treatment and procedure

There are several medical treatments and procedures that could be a risk factor for endometrial cancer.

• Oestrogen-only hormone replacement therapy:

  • This therapy could raise endometrial cancer risk because it exposes the uterine lining to prolonged oestrogen without the balancing effect of progesterone. 

• Tamoxifen:

  • Commonly used in breast cancer treatment, this drug acts like an anti-oestrogen in breast tissue but behaves like an oestrogen in the womb. 
  • The use of this drug, especially after menopause, may increase the risk of endometrial cancer depending on the dose and duration.

• Radiation therapy:

  • A history of radiation therapy directed at the pelvic region for other cancers could increase the chance of developing endometrial cancer later in life.

If you are concerned about your endometrial cancer risk factors, consulting a gynaecological oncologist may be worth considering. Schedule an appointment with Thomson Women's Clinic & Cancer Surgery to discuss your concerns and determine the next steps.

When to see a doctor

You may consult a doctor regarding endometrial cancer if you experience symptoms, have specific medical histories, or possess certain risk factors that require professional monitoring. The primary reasons to seek medical advice include:

Abnormal vaginal bleeding

If you have gone through menopause, any vaginal bleeding or spotting is considered abnormal and should be evaluated. Although in many cases it may not indicate something serious, postmenopausal bleeding could also be a warning sign of endometrial cancer.

Meanwhile, if you are still menstruating, you should be concerned if you have any bleeding between periods, unusually heavy periods, or abnormal discharge, as this is the most common symptom of endometrial cancer.

High-risk genetic conditions

If you have a family history of Lynch syndrome (a type of hereditary colon cancer) or endometrial and ovarian cancers, it is recommended that you consult a doctor.

If you are found to have Lynch syndrome or another high-risk genetic condition, your doctor may recommend regular endometrial monitoring, often including periodic endometrial biopsies starting around age 30-35, even if you have no symptoms.

Screenings for endometrial cancer

As of now, there are no routine screening tests for endometrial cancer in women who have no symptoms or are at average risk. When your doctor needs to investigate symptoms or monitor a high‑risk condition, they will usually start with a transvaginal ultrasound and may follow this with an endometrial biopsy.

Transvaginal ultrasound

A transvaginal ultrasound is an imaging test where your doctor inserts an ultrasound probe into the vagina to measure the thickness of your womb lining. While this scan provides important initial information, it cannot definitively distinguish between cancer, precancerous cells, or benign conditions like polyps, so if any abnormal results are detected, this test is usually followed by an endometrial biopsy.

Endometrial biopsy

An endometrial biopsy is the definitive method for diagnosing endometrial cancer. Your doctor collects a small tissue sample from your womb lining, which is then examined under a microscope for signs of cancer or precancerous cells.

If you are unsure which test is right for you, schedule an appointment with Thomson Women's Clinic & Cancer Surgery.Our gynaecological oncologist can help provide an overview of your condition and provide recommendations on the appropriate tests.

Factors that lower the risk for endometrial cancer

Knowing which factors may lower your risk of endometrial cancer could help you take steps to mitigate this condition. It might also help you to have more informed conversations with your doctor about which choices and habits are best for your body. 

Oral contraceptive pills

Oral contraceptive pills, particularly combined pills that contain both oestrogen and progestin, may lower your risk of developing endometrial cancer because these medications alter your body's hormonal balance.

These pills also suppress ovulation and reduce the natural swings in oestrogen production from your ovaries, which contributes to a thinner and more stable womb lining.

Intrauterine contraceptive devices

Intrauterine devices (IUDs) could help to lower your risk of developing endometrial cancer by changing the biological and hormonal environment inside your womb. How well this protection works depends on the type of device used.

Hormonal IUDs may release a steady, local dose of progestin directly into your womb to stop the effects of oestrogen from growing cells quickly and out of control.

On the other hand, non-hormonal copper IUDs work differently. The copper triggers a localised inflammatory and immune response in the womb that may change the local environment. It could be associated with a lower risk of endometrial cancer, but the evidence is not as strong or consistent as for hormonal IUDs. 

Pregnancy and breastfeeding

Pregnancy and breastfeeding could lower your risk of developing endometrial cancer mainly by interrupting your exposure to oestrogen. During the 9-month pregnancy, your menstrual cycles cease, and your body produces exceptionally high levels of progesterone.

Meanwhile, breastfeeding further extends these protective hormonal benefits. When you breastfeed, it often suppresses ovulation, which keeps your oestrogen levels lower for a period of time. This reduces the number of menstrual cycles and may further decrease the amount of oestrogen‑driven cell growth in the uterine lining.

Healthy diet and regular exercise

Maintaining a healthy diet and staying physically active are two of the most direct ways to lower your endometrial cancer risk. Here are some tips that you could try, including:

• Aim for a balanced diet rich in vegetables, fruits, whole grains, and legumes to help keep your blood sugar and insulin levels stable.

• Limit sugary, high-calorie, and highly processed foods and beverages, which may contribute to weight gain and insulin resistance.

• Include regular physical activity, which helps lower circulating oestrogen and insulin and supports healthier hormone balance over time.

FAQ

Can you get endometrial cancer even without any risk factors?

Yes. Although risk factors increase your likelihood of developing endometrial cancer, they are not necessary for the disease to occur. Some women who are diagnosed have no known risk factors at all. For this reason, any new or unusual vaginal bleeding is worth checking with your doctor, even if you consider yourself low risk.

How aggressive is endometrial cancer?

What are the risk factors for endometrial serous carcinoma?

Where is the most likely place for endometrial cancer to spread?

Endometrial cancer is most likely to spread first within the pelvis, especially to nearby pelvic tissues and lymph nodes. Meanwhile, when endometrial cancer has become distant metastasis (the spread of cancer cells from the site of the primary tumour to other organs or tissues), it is most likely to spread to the lungs.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised advice based on your unique conditions, schedule an appointment with Thomson Medical today.

References:

Beining, R. M., Dennis, L. K., Smith, E. M., & Dokras, A. (2008). Meta-analysis of intrauterine device use and risk of endometrial cancer. Annals of epidemiology, 18(6), 492–499. https://doi.org/10.1016/j.annepidem.2007.11.011