Risks for uterine cancer

Some things can affect your risk, or chance, of developing cancer. Certain behaviours, substances or conditions can increase or decrease the chance. Most cancers are the result of many risks. But sometimes cancer develops in people who don’t have any risks.

In Canada, the incidence rates for uterine cancer have increased over the past 30 years. Most uterine cancers are found in women who have gone through menopause. At this time, we can’t say what the risk is for transgender, non-binary and gender-diverse people.

Some of the things that increase the risk for uterine cancer may also cause precancerous conditions. One of those precancerous conditions is called endometrial intraepithelial neoplasia (EIN), in which the lining of the uterus (endometrium) becomes thick. This thickening of the lining happens when abnormal endometrial cells grow. This condition is not cancer, but it can sometimes become uterine cancer if it is not treated. Find out more about EIN.

If you have a genetic condition that increases your risk for uterine cancer, you may need to visit your doctor more often than usual. Talk to your doctor about your risk and whether you need to have certain tests to check for uterine cancer.

You can’t change some of these risks. But in other cases, there are things you can do to lower your risk.

The following can increase your risk for uterine cancer:

Estrogen-only hormone replacement therapy (HRT)

Number of menstrual periods

Excess weight

Tamoxifen

Diabetes

Polyendocrine metabolic ovarian syndrome (PMOS)

Lynch syndrome

Cowden syndrome

Estrogen-producing ovarian tumours

The following can decrease your risk for uterine cancer:

Giving birth

Physical activity

Birth control pills

Hormone replacement therapy, or HRT, uses female sex hormones (estrogen or progesterone or both) to manage the symptoms of menopause, such as hot flashes, vaginal dryness and mood swings. Using estrogen-only HRT (without progesterone) increases the risk for uterine cancer. Because of the risk, estrogen-only HRT is usually recommended only if you have had a hysterectomy, which is surgery to remove the uterus (womb).

Taking combined HRT, which is estrogen and progesterone, does not increase the risk for uterine cancer.

Talk to your doctor about hormone replacement therapy.

Women who start having their period before the age of 12 (called early menstruation) or stop having their period after the age of 55 (called late menopause) have an increased risk of uterine cancer. This is because more menstrual periods over a lifetime increases the amount of estrogen the body makes, which increases the risk of developing uterine cancer.

Excess weight and obesity increase the risk for uterine cancer. This could be because having too much fat tissue raises the level of estrogen in the body, and too much estrogen increases the risk for uterine cancer. Excess weight can also increase the level in the blood of 2 other hormones, insulin and insulin-like growth factor-1. These hormones manage the normal growth of the body’s bones and tissues. Having higher levels of these hormones may help some tumours grow.

Learn more about how to have a healthy body weight.

Tamoxifen is a hormone therapy drug used to treat certain cancers. It is one of the most common hormone drug therapies doctors prescribe for breast cancer. Women treated with tamoxifen for 2 or more years have a higher risk of developing uterine cancer than women who haven’t taken tamoxifen. The benefits of taking tamoxifen usually outweigh the risks.

Diabetes (also called diabetes mellitus) is a chronic disease in which the pancreas can’t make enough insulin or the body can’t properly use the insulin it makes. Without proper management, diabetes can lead to high blood sugar levels. Diabetes increases the risk for uterine cancer.

Polyendocrine metabolic ovarian syndrome (PMOS) is a condition that can change the normal hormone cycle and ovulation process. Having PMOS increases your risk of developing uterine cancer.

This syndrome was previously called polycystic ovarian syndrome (PCOS).

Lynch syndrome is an inherited condition that a change (mutation) in one of the genes involved in DNA mismatch repair causes. These genes normally correct mistakes when DNA is copied during cell division. With Lynch syndrome, mismatch repair genes don’t work properly and don’t repair damaged cells. Eventually, these abnormal cells build up and can become cancerous.

Lynch syndrome increases the risk for uterine cancer. Women who have Lynch syndrome who develop uterine cancer tend to do so at a younger age when compared to other women who develop uterine cancer.

Having surgery to remove the uterus before cancer develops, known as a prophylactic hysterectomy, may be an option for some women with Lynch syndrome. Talk to your doctor about all the risks and benefits of the surgery and if it’s the best choice for you.

Lynch syndrome is sometimes called hereditary non-polyposis colorectal cancer (HNPCC).

Cowden syndrome is an inherited condition in which many non-cancerous (benign) growths form in the skin, breast, thyroid, colon and intestines and inside the mouth. These growths are called hamartomas. A mutation in a gene known as PTEN causes this condition. Cowden syndrome increases the risk for uterine cancer.

Some types of tumours in the ovaries make estrogen. Because those tumours increase the total amount of estrogen in your body, it can increase your risk for uterine cancer if you have those tumours.

During pregnancy, estrogen levels in the body drop. The more often a woman gives birth, the less estrogen her body makes during her lifetime and the lower the risk of uterine cancer. Women who have never given birth have an increased risk of uterine cancer.

Being physically active reduces the risk for uterine cancer. Women who don’t get much physical activity have a higher risk of uterine cancer.

Learn more about how to move more, sit less.

Birth control pills (oral contraceptives) are designed to prevent pregnancy. Birth control pills reduce your risk for uterine cancer.

Learn all about the birth control pill.

The following factors have been linked with an increased risk of uterine cancer, but researchers need more information to know for sure that they are risks:

• radiation therapy to the pelvis
• sitting for long periods of time
• family history of uterine cancer
• high blood pressure (hypertension)
• diethylstilbestrol (DES), which is a form of estrogen made in a lab
• a diet with a high glycemic load, which is a measure of how quickly certain types and amounts of food such as carbohydrates raise blood sugar levels
• being a tall adult

The following have been linked with a decreased risk of uterine cancer, but researchers need more information to know for sure that they lower the risk:

• intrauterine devices (IUDs), a type of birth control
• drinking coffee (caffeinated or decaffeinated)

To make decisions that are right for you, ask your doctor questions about risks. Learn how you may be able to prevent some types of cancer and what you can do to reduce your risk.