Why does obesity increase the risk for endometrial cancer?

Posted in endometrial cancer, causes; Posted 3 years ago by Andreas Obermair

As rates of obesity continue to increase, the numbers of women diagnosed with endometrial cancer is also expected to rise.

Obesity is a major risk factor for developing endometrial cancer. The relationship of obesity and endometrial cancer is stronger for endometrial cancer than for any other type of cancer. According to the American Cancer Society, compared to women who are a healthy weight, endometrial cancer is twice as common in overweight women (body mass index (BMI) 25 to 29.9), and more than 3 times as common in women who are obese (BMI 30 or higher).

Over 50% of endometrial cancers are attributable to obesity. Endometrioid (type 1) is the subtype of endometrial cancer that is predominantly linked to obesity, rather than type 2 (non-endometrioid such as serous) however both subtypes report an increased risk with obesity.

How do we explain this link?

Overweight or obese people often tend to have chronic inflammation. While it is largely unknown why obese people have higher inflammation, it changes how the body manages hormones such as insulin (hormone that regulates sugar) and oestrogen (sex hormone responsible for the development and regulation of the female reproductive system).

Inflammation can also cause the pancreas to produce more insulin, and the extra fat tissue also produces additional estrogen. Too much insulin and estrogen hormones may cause cells to divide and reproduce uncontrollably, and could result in endometrial tumour growth.  

Obesity and endometrial cancer treatment

Being overweight or obese can also impact treatment of endometrial cancer, with the risk of complications particularly increasing in obese women. Women who are obese are also more likely to have other disorders such as diabetes, hypertension and cardiovascular disease, which can have a negative impact on endometrial cancer treatments and survival. Sometimes this means that major surgery may be too risky and alternative options for endometrial cancer treatment may need to be explored.

Is there a link between obesity and other types of gynaecological cancers?

Regarding other types of gynaecological cancer such as ovarian cancer and cervical cancer, the evidence is less consistent.

Weight loss linked to lower risk of endometrial cancer

Both diet and physical activity have been proved to be associated with a decreased risk of endometrial cancer. A recent interesting study found that losing weight can reduce the risk of endometrial cancer in women who have gone through menopause. In a study of more than 35,000 women aged 50 to 79 years women were weighed at the beginning of the study, and again 3 years later to assess their weight change. Researchers followed the participants for an average of 11 years to assess who was diagnosed with endometrial cancer.

The researchers found that obese women who planned to lose weight and lost 5% or more of their body weight had a 56% reduced risk of endometrial cancer. Overweight or obese women who reached a normal BMI had the same risk as women who maintained a normal BMI.

In summary, this study shows it’s never too late to benefit from weight loss.

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