December 20, 2012
For Menopausal Women, Obesity Can Increase Cancer Risk
Connie K. Ho for redOrbit.com — Your Universe Online
Researchers from the University of Colorado Cancer Center recently revealed that maintaining a healthy lifestyle during menopause could help reduce the risk of breast cancer later on.
To begin, females who are obese and postmenopausal have a greater risk of later developing breast cancer. They also found that the cancer that these women get can be more aggressive than for their healthier counterparts. The findings of the study were recently featured in the journal Cancer Research.
The team of investigators was interested in exploring ways of limiting the risk for breast cancer.
“By using nutrient tracers for fat and sugar, we tracked where the body stored excess calories. In lean models, excess fat and glucose were taken up by the liver, mammary and skeletal tissues. In obese models, excess fat and glucose were taken up by tumors, fueling their growth,” explained the study´s lead author Erin Giles, a postdoctoral researcher at the Cancer Center, in a prepared statement.
The research results demonstrated that extra calories can go to tumor growth, while extra calories for leaner individuals tend to be sent to healthy tissue.
“This implies that the menopausal window may be an opportunity for women to control their breast cancer risk through weight management,” continued Giles.
The study included a section that looked at the tumors of obese animals and how these animals had higher levels of progesterone receptor, which gives tumors a metabolic advantage over healthy tissue. The researchers recruited the help of gene analysis experts David Astling and Aik-Choon Tan to help analyze the 585 human breast cancer cases. They discovered that human tumors that express the progesterone receptor also have the same metabolic advantage, and the group decided to test the type II diabetes drug Metformin in the experiment on postmenopausal breast cancer.
“Basically, we saw an abnormal metabolic response to fat and sugar in the obese that, in many ways, mirrors the response to fat and sugar in Type II diabetes,” said Giles. “With treatment, tumor size was dramatically decreased in the obese, and tumors showed reduced expression of the progesterone receptor.”
Furthermore, the scientists found that for obese women who were entering menopause, weight gain is particularly difficult. They discovered that adding extra pounds during menopause can lead to an inability to keep extra calories in healthy tissues and a rise in the growth of tumors. Moving forward, the group will continue to study the impact of intervention on menopausal weight gain and hope to further elucidate the affect of diet and exercise on tumor growth.
“While drugs may be useful in controlling breast cancer risk in obese, postmenopausal women, our results imply that a combination of diet and exercise may be equally if not more beneficial,” concluded Giles in the statement.