Postmenopausal women with type 2 diabetes are nearly 30 percent. more likely to develop breast cancer than their peers without impaired glucose metabolism, according to the British Journal of Cancer.
Such conclusions were reached by scientists from the International Prevention Research Institute (i-PRI) in Lyon, who analyzed the results of 40 different studies on a potential link between breast cancer and diabetes. They covered over 56 thousand. women with breast cancer from four continents.
It turned out that postmenopausal women with type 2 diabetes had 27 percent. higher risk of breast cancer than their peers without disturbing glucose metabolism. However, no similar association was observed in premenopausal women with type 2 diabetes or in women with type 1 diabetes.
“So far, we do not know the mechanism that could explain the relationship between type 2 diabetes and a higher risk of breast cancer” – comments the lead author of the study, Prof. Peter Boyle, president of i-PRI.
As the researcher reminds, there is a belief that overweight (and especially obesity) associated with type 2 diabetes may be partly responsible for it. It is accompanied by changes in the hormonal balance, which may contribute to the development of cancer.
Obesity is known to increase the risk of breast cancer in postmenopausal women by up to 30%. In Great Britain, for example, over 4 annual cases of this cancer are attributed to overweight and obesity.
According to prof. Boyla, however, it is also possible that there is a direct link between diabetes and cancer.
In previous epidemiological studies it was observed that people with type 2 diabetes are at a higher risk of, inter alia, for cancer of the pancreas, liver, colon.
Scientists speculate that this may be related to the so-called insulin resistance, which underlies this form of diabetes. It is manifested by a decrease in the sensitivity of tissues (e.g. muscle) to insulin, which makes the cells unable to properly use glucose, which is their basic fuel. As a result, the level of this sugar in the blood rises.
Initially, the body tries to deal with this phenomenon by increasing the production of insulin by the pancreas. And because one of the properties of insulin is to stimulate cell division, higher levels of insulin in the body can stimulate tumor growth.
The authors of the latest work emphasize that it is not yet known whether the relationship between type 2 diabetes and breast cancer in postmenopausal women is causal.
However, they encourage women to try to maintain a healthy body weight, because it increases the chances of avoiding both type 2 diabetes and breast cancer. (PAP)
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