How can polycystic ovarian syndrome (PCOS) cause endometrial cancer?

Daniel A. Dumesic, MD
Reproductive Endocrinology
There are two mechanisms that can link polycystic ovary syndrome (PCOS) to endometrial carcinoma (cancer). If women do not ovulate, they do not make a hormone called progesterone, which is intended to clean up the lining of the uterus every month with the menses.

In the absence of ovulation, estrogen is produced and the endometrium (lining of the uterus) continues to grow. Because progesterone is not being made, there’s no stop signal to the growth of the endometrium. Over many years, one will experience long-term irregular bleeding and ultimately an increased risk of endometrial carcinoma, which is originating from this endometrium that’s constantly been growing over the long term without a mechanism to really stop its growth. That’s the common mechanism associated with endometrial carcinoma in PCOS.

A second mechanism involves insulin, which is also a hormone that causes cell proliferation. Many PCOS women have a type of insulin-resistance that is independent and additive with that of obesity so that their insulin levels in the circulation are increased. This elevation in circulating insulin levels can continuously stimulate the cells lining the uterine cavity and may also increase the risk of developing endometrial carcinoma.
Irregular menstrual periods and the absence of ovulation cause women with polycystic ovarian syndrome (PCOS) to produce estrogen, but not progesterone. Without progesterone, which causes the endometrium to shed each month as a menstrual period, the endometrium may grow too much and undergo cell changes. This is a pre-cancerous condition called endometrial hyperplasia. If the thickened endometrium is not treated, over a long period of time it may turn into endometrial cancer.

Continue Learning about Endometrial (Uterine) Cancer

Endometrial (Uterine) Cancer

Starting in the lining of a womans uterus, endometrial cancer is caused when your body has a hormonal imbalance.When you have too much of the hormone estrogen relative to the hormone progesterone, the lining of the uterus grows to...

o thick and allows tumors to grow. The hormonal imbalance may be caused by using estrogen to treat menopause or by having ovarian tumors that produce estrogen. Obesity also increases your risk; fat cells make extra estrogen that isnt balanced out with more progesterone. Hormonal birth control can reduce your risk of endometrial cancer, although keep in mind it has risks of its own. Studies show you can remain protected from this cancer for up to 10 years after you stop taking hormonal birth control. Call your doctor if you have vaginal bleeding or unexplained weight loss. When found early, endometrial cancer is very treatable. Aggressive treatments may include removal of parts of the female reproductive system, including the uterus and ovaries.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.