Endometrial cancer is a cancer that affects the uterus — or more specifically the endometrium, which lines the uterus. It is the most common cancer of the female reproductive organs in the United States, according to the American Cancer Society.

There are several ways to reduce the risk of developing endometrial cancer and, in some cases, prevent it entirely. Let's explore how to lower your risk.

What is endometrial cancer?

Endometrial cancer develops when healthy endometrial cells start to mutate and overgrow. These cells do not have the lifecycle of normal cells, so they quickly multiply, and tumors can then develop and spread to other parts of the uterus and the body.

"It's the fourth most common cancer of all cancers in women in the United States," says Dr. Behrouz Zand, a gynecologic oncologist with Houston Methodist. "It typically affects postmenopausal women, usually age 55 and older, but it can happen in women under the age of 50. In fact, there are recent studies showing that the rates of endometrial cancer in this country are rising even among younger women."

Endometrial cancer risk factors

"People live longer these days, and so the longer you live, the more likely you are to possibly get cancer," Dr. Zand says. "Obesity is a huge risk factor for getting endometrial cancer, particularly Type 1 endometrial cancer, which is the most common type."

Type 1 endometrial cancer is due to changes in the body's balance of estrogen and progesterone. Both hormones affect the lining of the uterus, and when the body has too much estrogen it overstimulates growth.

Women with conditions such as obesity, polycystic ovarian syndrome (PCOS), and type 2 diabetes can experience higher levels of estrogen than progesterone hormone, putting them at increased risk of developing Type 1 endometrial cancer.

Additionally, those that experience early menstruation before age 12 or menopause after 55 are at increased risk. That's because experiencing more menstrual cycles during a lifetime means you've had more estrogen exposure.

This is especially so for women who have never experienced pregnancy. The body produces more progesterone during pregnancy to prevent ovulation and uterine contractions that could cause preterm labor. So pregnancy can have a protective effect against Type 1 endometrial cancer because each pregnancy lowers your overall lifetime exposure to estrogen.

However, it's important to note that not all endometrial cancers are related to hormonal imbalances or obesity. Type 2 endometrial cancer, which is less common but often more aggressive, can develop in women who are at a healthy weight and have no underlying medical conditions.

Women with Lynch syndrome, a genetic form of colorectal cancer, are also at higher risk of developing endometrial cancer. Tamoxifen, a drug used in breast cancer treatment and prevention, can act like estrogen in the uterus and can be a risk factor for endometrial cancer, according to Dr. Zand.

"If you have breast cancer or had breast cancer and are put on tamoxifen long term, it's something to be aware of," Dr. Zand says.

Regardless of the type, it's crucial for women to be aware of the signs and symptoms of endometrial cancer and to consult with their healthcare provider if they experience any unusual symptoms.

Endometrial cancer symptoms

"The most common symptom of endometrial cancer is abnormal vaginal bleeding," Dr. Zand says. "This can happen before or after menopause. What women see is bleeding between their periods or spotting between periods that wasn't there before."

Other signs can include pelvic pain or bleeding or spotting that happens after a woman's final period.

How to lower your risk for endometrial cancer

Keep up with healthy habits to control your weight

Eating a healthy diet and getting regular physical activity can be two of the most important habits to help protect against many conditions, including cancer. The American Cancer Society (along with many other health organizations) recommends that adults should aim for a minimum of 150 minutes of moderate physical activity a week and eat a diet focused on vegetables, fruit and whole grains and limiting red and processed meats, highly processed foods and sugary drinks. It's also recommended to limit alcohol intake to a drink a day for women or two drinks a day for men, or to not drink at all.

"The reason why obesity is at risk factor for endometrial cancer is because excess body fat increases your level of estrogen in the body," says Dr. Zand. "Your fat tissue actually convert other hormones into estrogen, which leads to the higher estrogen levels."

Carrying extra weight can also put you at risk of type 2 diabetes, which is another risk factor.

"In patients with diabetes, the body does not use insulin effectively, which leads to higher levels of insulin in the blood," Dr. Zand says. "This excess insulin can encourage endometrial cells to grow more rapidly, which can increase your risk of endometrial cancer."

Balancing hormones: the importance of progesterone with estrogen therapy

For some perimenopausal women, hormone therapy is a way to treat some of the side effects of the transition to menopause. Estrogen is often used to combat perimenopausal symptoms such as hot flashes and vaginal dryness, and to help prevent osteoporosis. For women that still have a uterus, taking estrogen therapy without progesterone can increase the risk of endometrial cancer.

"Women can get endometrial cancer because what happens with unopposed estrogen, as we call it, is that the lining develops and gets overstimulated," Dr. Zand says. "You actually need progesterone to counterbalance that effect. If you don't get progesterone, this increases your risk of cancer."

When estrogen therapy is paired with progesterone therapy, the risk of endometrial cancer does not increase. But this hormone therapy combination can increase the risk of breast cancer and blood clots.

Anyone who wants to get relief from menopausal symptoms should talk to their doctor. Working with your doctor to understand your individual risk for conditions like endometrial cancer can help you make an informed decision about whether hormone therapy or other treatments are right for you.

Use birth control if it's right for you

Hormonal birth control — such as oral contraceptives, often called "the Pill" — is most often used to prevent pregnancy and treat certain issues, such as heavy or irregular periods, endometriosis and more. Aside from improving acne and excessive facial and body hair, it also has other effects, including being protective against endometrial and ovarian cancer.

"The Pill has progesterone in it, so because of that, it's actually protective for your uterine lining," Dr. Zand says. "If you use an IUD, there are two types that are available in the United States. One is the copper IUD, which does not increase your risk of endometrial cancer. The other, the Mirena, does release progesterone into the uterus as part of its contraceptive, so it is protective against endometrial cancer as well."

Like with any medication, there can be risks and side effects — so hormonal birth control isn't right for everyone. Work with your doctor to understand if hormonal birth control is a good choice for your health.

Manage your health & get regular checkups

Working with your doctor to stay on top of your health can help you potentially catch cancer (or any condition) earlier when it's potentially easier to treat. Getting your yearly Well Woman exam and any screening tests based on your age and health history, such as mammogram and colonoscopy, are all good actions to take to stay healthy as you age. And managing any chronic conditions you might have, such as type 2 diabetes, PCOS and others, can help you keep your individual risk in check.

Developing good self-monitoring habits can help you stay aware of any changes in your body. Tracking your periods can give you an understanding of what's normal for your menstrual cycle. It can help you spot bleeding in between periods ꟷ which can be a sign of endometrial cancer ꟷ as well as track menstrual cramps, cycle duration and other symptoms to see how your period changes as you age and approach menopause.

"This is a type of cancer that, fortunately, can be easily detected in its early stages," Dr. Zand says. "A lot of people may forget about some of these symptoms that happen or not think they are serious, but it may come up during your checkups. Typically, it's caught because of this abnormal vaginal bleeding, that tips off your doctor to do a biopsy that will give us the diagnosis."