Obesity and Endometrial Cancer

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Obesity has been identified as a contributing factor in many women’s cancers, including breast cancer, cervical cancer, ovarian cancer, and endometrial cancer.

What Is Endometrial Cancer?

The endometrium is the inner lining of the uterus. Thus, endometrial cancer starts in the endometrium. According to the American Cancer Society, nearly all cancers of the uterus are endometrial cancers—that is, nearly all cancers of the uterus begin in the endometrium.

The American Cancer Society (ACS) also notes that, in the United States, endometrial cancer is the most common cancer of the female reproductive organs (ovaries, uterus, cervix, fallopian tubes). The ACS estimates that approximately 54,870 new cases of uterine cancer will be diagnosed in 2015, and over 10,000 women will die from cancers of the uterus.

Endometrial cancer occurs most often in women aged 55 and older. The average chance of a woman being diagnosed with endometrial cancer in her lifetime is approximately 1 in 37.

Obesity Is a Risk Factor

As the ACS notes, many of the risk factors for development of endometrial cancer are associated with an effect on estrogen levels.

It is known that adipose (fat) tissue produces excess amounts of estrogen. In fact, adipose tissue is the largest source of estrogen in women after menopause. Thus, at a time when estrogen levels would normally be falling, those women who have higher amounts of adipose tissue are experiencing abnormally higher levels of estrogen as well, and high levels of estrogen have been linked to an increased risk of endometrial and breast cancer.

According to the ACS, endometrial cancer is twice as likely to occur in women who are overweight as compared with women who maintain a healthy weight, and more than three times as likely to occur in women who are obese.

Obesity and the Molecular Link With Cancer

In addition, obesity often causes the body to have increased levels of insulin and a related factor known as insulin-like growth factor-1 (IGF-1), which, in addition to its normal physiologic functions of stimulating growth during childhood and helping to repair and build muscle tissue in adulthood, may promote the development and growth of certain tumors, particularly when it is present at higher-than-normal levels, as it is in obesity.

Obesity is also associated with greater systemic inflammation on a chronic basis, and this has been associated with an increased risk of cancer.

Furthermore, adipose cells produce other hormones, known as adipokines, that can stimulate cell growth. One of these growth-stimulating adipokines is leptin, which is also known as a satiety factor, and is present at higher levels in obese individuals.


American Cancer Society. Endomterial (uterine cancer): key statistics. Accessed online at http://www.cancer.org/cancer/endometrialcancer/detailedguide/endometrial-uterine-cancer-key-statistics on May 11, 2015.

Ballard-Barbash R, Berrigan D, Potischmann N, Dowling E. Obesity and cancer epidemiology. In: Berger NA, editor. Cancer and Energy Balance, Epidemiology and Overview. New York: Springer-Vertag New York, LLC, 2010.

Ahlgren M, Melbye M, Wohlfahrt J, et al. Growth patterns and the risk of breast cancer in women. N Engl J Med 2004;351:1619-1626.

Lorincz Am, Sukumar S. Molecular links between obesity and breast cancer. Endocr Relat Cancer 2006;13:279-292.

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