A new study shows that a woman's weight before and after her breast cancer diagnosis has an impact on how well she will survive the disease. Maintaining a healthy weight helps women avoid breast cancer. It's not the only prevention, of course, but mounting evidence shows that being overweight or obese, increases the odds of getting the cancer women fear most.
"Lose weight to prevent and survive breast cancer."
New evidence shows that obesity can also increase a woman's chances of dying from the disease.
"We found that obese women diagnosed with breast cancer had a greater chance (69% increased risk) of dying from their disease when compared to normal weight women diagnosed with breast cancer," said the study's lead author, Christina Dieli-Conwright, PhD., assistant research professor at City of Hope National Medical Center in Duarte, California.
She added, the relationship between dying and being obese or overweight appears to relate with the type of breast cancer a woman has. Women with estrogen receptor positive (ER+) had the highest risks.
The study involved nearly 4,000 breast cancer survivors who had been diagnosed with invasive breast cancer — cancer that has spread beyond the breast ducts - between 1995 and 2006. Of the 3,995 women studied, 262 died of breast cancer through 2007.
Overweight or obese women with a history of estrogen receptor-positive breast cancer had the highest risks. Higher death rates were not seen in women with estrogen receptor-negative cancer. Obese women typically having more estrogen circulating in their bodies, which is likely the reason for the difference.
Researchers defined obesity as a body mass index (BMI) of 30 or higher. The authors determined BMI from questionnaires participants completed reporting height and weight at baseline (the beginning of the study) and at age 18.
Women who were obese at baseline had a 69 percent higher risk of dying of their breast cancer than did nonobese women, Dieli-Conwright said. This same increased mortality, or death, risk was present in women who were overweight (BMI of 25 to 29) at age 18.
They found that the higher the BMI, the greater the risk of dying of breast cancer for women with estrogen-dependent cancer.
"We understand that obesity can be a contributing factor to a number of chronic diseases," said Russell Ricci, M.D., Chairman, dailyRx Medical Advisory Board. "These findings add to that knowledge and provide women just one more reason to work toward achieving and maintaining their ideal weight."
Dieli-Conwright agrees. "Maintaining a healthy body weight is critical not only for cancer prevention but also to improve cancer survivorship," she said.