We’ve long known obesity leaves people at a heightened risk of disease and premature death. Now, researchers say it could also impact how early breast cancer spreads in women.
Unique changes in the bodies of women with obesity are helping breast cancer to become invasive and typically more advanced, spreading into surrounding breast tissue, new Oklahoma University research says.
The changes were seen in cancer tumors and the surrounding cells. The researchers discovered higher levels of an enzyme known as Sulfatase 2 in tumor cells, too.
Although more work needs to be done to determine how these changes contribute to invasive breast cancer, the findings could help doctors better treat patients.
“This could be why women with obesity are at higher risk for invasive breast cancer,” Bethany Hannafon, an assistant professor at the university’s College of Medicine, explained in a statement. “The changes that the cancer cells are undergoing are allowing them to survive and thrive.”
So, what are the changes?
First, the area surrounding the cancer was more inflamed in women with obesity, as immune cells arrived and sped up tumor growth.
These cells normally fight off disease, but can be reprogrammed by tumors to support cancer, according to New York’s Memorial Sloan Kettering Cancer Center.
And, the cells that make up their tumors seemed to be able to survive better under stress, and there were differences in the tumor cells and cells around them, the researchers said.
The enzyme, a protein that accelerates chemical reactions in the body, has previously been tied to breast, lung, liver and other forms of cancer.
Future research will focus on its role in invasive breast cancer, the researchers said.
While breast cancer survival rates have improved over the past 20 years, the number of women diagnosed with invasive breast cancer has not declined.
About 321,910 new cases of invasive breast cancer will be diagnosed this year, the American Cancer Society estimates.
Most breast cancers are invasive, but there are two types that are most common: invasive ductal carcinoma and invasive lobular carcinoma.
Invasive ductal carcinoma is the most common type of breast cancer, and makes up 80 percent of invasive cases, according to the society.
This type spreads in cells that line the milk duct in the breast, breaking through the wall of the duct and growing into nearby tissue.
Invasive lobular carcinoma, which makes up 10 percent of invasive cases, start in the breast glands that make milk.
There is currently no way of determining which women with noninvasive tumors later develop into invasive ductal carcinoma,
“As a result, many women with [noninvasive breast cancer] receive the same treatments used for [invasive ductal carcinoma], including surgery, radiation and sometimes hormone therapy,” Hannafon said.
“Overtreatment is a major concern, but if we had better ways of determining risk, unnecessary treatments could potentially be reduced,” she noted.
Breast cancer is the most common cancer in women in the U.S. – other than skin cancers. It accounts for about 30 percent of all new female cancers each year.
Obesity is a known risk factor for invasive breast cancer and other forms.
More than 100 million Americans live with obesity, some 40 percent of whom are women.
