Endometrial Cancer Risk Factors

What Increases Your Risk of Endometrial Cancer?

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Endometrial cancer is a cancer of the lining of the uterus, the endometrium. It is the most common form of uterine cancer for women. The direct causes of endometrial cancer are not known, but doctors have identified several risk factors for it.

While risk factors may raise your chances of developing endometrial cancer, they do not mean you will get it or that they caused the cancer. The American Cancer Society notes that many women with one or more risk factors never develop endometrial cancer, while some women with this cancer have no known risk factors.

 

Estrogen May Increase Your Risk of Endometrial Cancer

While we cannot yet pinpoint exactly what causes endometrial cancer, studies suggest that higher levels of estrogen and longer exposure to estrogen over many years may be associated with endometrial cancer development.

Estrogen is a naturally occurring hormone made in the ovaries, along with the hormone progesterone. These hormone levels fluctuate during the monthly cycle. During and after menopause, the body stops producing these hormones. This is what causes the effects of menopause, like hot flashes, night sweats, and vaginal dryness.

Reasons you might have elevated estrogen levels or longer exposure:

  • Estrogen-Only Hormone Therapy: To alleviate the bothersome side effects of menopause, some women are prescribed hormone replacement therapy. This can be either estrogen or estrogen along with progestin (a synthetic version of progesterone), depending on whether or not they still have their uterus. Estrogen can cause the lining of the uterus to grow (endometrial hyperplasia) if a woman still has her uterus, so she will need to take progestin to counteract it. There is a risk of developing uterine cancer if this occurs. Thus, taking estrogen without the aid of progestin if you still have a uterus may increase your risk of endometrial cancer.
  • Obesity: Even though the ovaries are no longer producing estrogen after menopause as they once were, estrogen can still be found in the body in adipose tissue (fat). This is normal for all women. Researchers believe that because obese women have more adipose tissue, they are at an increased risk of developing endometrial cancer because they have higher levels of estrogen. Unfortunately, women who are obese and also have endometrial cancer suffer from an increased risk of death from the disease. Keep in mind that women at healthy weights are also vulnerable to endometrial cancer -- it isn't exclusive to obese women.
  • Many Years of Menstruation: Starting menstruation early or beginning menopause late also increases your risk of endometrial cancer. Again, estrogen is a factor in why this may increase your risk. In menstruating women, the endometrium is exposed to estrogen every cycle. The more cycles you have, the more estrogen exposure your endometrium experiences.
  • PCOS or Irregular Ovulation: Women who experience irregular ovulation, like those who suffer from polycystic ovary syndrome (PCOS), face an increased risk of endometrial cancer. In these women, estrogen is being produced and stimulating the growth (thickening) of the endometrial lining. However, if ovulation does not occur, the endometrial lining is not shed (as in normal, ovulating women) and is exposed to more estrogen. The result can be endometrial hyperplasia, which can lead to endometrial cancer.
  • Never Being Pregnant: Women who have never been pregnant are at an increased risk, especially those who suffer from infertility. The thinking behind this risk factor is that women who have never been pregnant may experience irregular ovulation, which is explained above.
  • Tamoxifen Use: Tamoxifen is an adjuvant therapy drug often prescribed for women with breast cancer. It binds to estrogen receptors in some tissues, blocking estrogen from binding and stimulating tissue growth. This prevents estrogen from fueling growth of some types of breast cancer. Unfortunately, Tamoxifen can also stimulate the growth of the endometrium.

Other Endometrial Cancer Risk Factors

Estrogen is not the only risk factor of endometrial cancer. Researchers have identified other risk factors for the disease:

  • Diabetes: Research shows that women who are diabetic are at an increased risk of endometrial cancer. This could be because obesity and diabetes are related.
  • Personal Health History of Breast or Ovarian Cancer: Women who have had breast or ovarian cancer have a small increase in the risk of developing endometrial cancer. The three diseases all share similar risk factors.
  • Lynch Syndrome: Also known as HNPCC (hereditary nonpolyposis colorectal cancer), Lynch syndrome is an genetic condition that increases a person's risk of cancer, especially colon cancer. Lynch syndrome primarily affects the digestive tract, but also increases the risk of of ovarian and endometrial cancer in women.

Source:

"Endometrial (Uterine) Cancer," American Cancer Society, 3/17/2015.

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