Uterine Cancer Risk Factors

Most uterine cancer is driven by estrogen. Doctors also call it endometrial cancer. The lining of the uterus grows in response to estrogen. Sometimes estrogen exposure is high, or not balanced by another hormone called progesterone, for a long time. When that happens, the lining can grow abnormally. It can sometimes turn into cancer. Many of the risk factors below trace back to this one mechanism. They can look unrelated on the surface.

Excess body weight is one of the strongest risk factors. Fat tissue converts a hormone called androgen into estrogen. This means the body makes extra estrogen, beyond what the ovaries produce. That matters most after menopause, when the ovaries stop being the main source. Diabetes and metabolic syndrome often occur alongside obesity. Both add further risk. A high-fat diet raises risk too. Part of the reason is its link to obesity.

Taking estrogen alone, without a progestin to balance it, raises risk substantially. This applies to certain hormone replacement therapy regimens used after menopause. Tamoxifen is a drug used to treat and prevent breast cancer. It also raises uterine cancer risk, though the yearly risk is small, under 1%. Anyone taking tamoxifen should still know this. Report unusual bleeding promptly.

Lifetime estrogen exposure matters too. Starting periods early, reaching menopause late, and never having been pregnant all extend how long the uterine lining is exposed to estrogen. That raises risk. Pregnancy, breastfeeding, and birth control pills or hormonal IUDs all lower risk. Largely, this is because they reduce that lifetime estrogen exposure.

Polycystic ovary syndrome, or PCOS, raises risk too. It works through the same hormone-balance effect. Endometrial hyperplasia is a thickening of the uterine lining. It raises risk directly. One form, called atypical hyperplasia, can be a direct precursor to cancer. Previous radiation to the pelvis, given to treat another cancer, is linked to higher risk as well.

Lynch syndrome is an inherited condition. It also raises colorectal cancer risk, and it sharply raises uterine cancer risk too. Cowden syndrome is a rarer inherited condition. It does the same. If uterine or colorectal cancer runs in your family, genetic counseling can help. This matters most if relatives were diagnosed young. Counseling can clarify whether one of these conditions applies to you.

Risk rises with age and is highest after menopause. Emerging research also links long-term use of certain chemical hair relaxers to higher risk. This association has been studied particularly in postmenopausal Black women. This research is newer than the other factors listed here. Black women are also more likely to be diagnosed with more advanced, aggressive disease. Researchers are still working to fully explain this disparity.

You cannot change your age or genetics. But several factors here are within some control. These include managing weight, treating diabetes, and discussing hormone therapy options carefully with your doctor. None of these guarantee prevention. Together, though, they meaningfully shift the odds. Knowing your personal risk factors should also shape how quickly any abnormal bleeding gets evaluated.

• Given my weight, hormone history, and family history, am I at higher risk for uterine cancer?
• Does my family history suggest I should be tested for Lynch syndrome?
• If I take tamoxifen or hormone therapy, what bleeding pattern should prompt me to call you?
• Any postmenopausal bleeding is a symptom, not just a risk factor — how quickly should that be evaluated?

• American Cancer Society — Endometrial Cancer Risk Factors