A new study funded by the National Cancer Institute and the California Breast Cancer Research Fund tells us that obesity not only raises the risk of developing breast cancer, but is now shown to increase the chances of dying from it.
According to a press release, “The study, conducted in nearly 4,000 breast cancer survivors, found that obesity is strongly linked to death due to breast cancer. In particular, overweight or obese women with a history of estrogen receptor-positive breast cancer, but not those with estrogen receptor-negative cancer, had a higher risk of dying of their disease,” said the study's lead author, Christina Dieli-Conwright, PhD, assistant research professor at City of Hope National Medical Center in Duarte, Calif.
The National Cancer Institute estimated that obesity and physical inactivity account for 25 to 30 percent of several major cancers – colon, breast, endometrial, kidney, and cancer of the esophagus.
The National Cancer Institute also reported that in 2002, about 41,000 – or 3.2 percent – of all new cases of cancer in the U.S. were estimated to be due to obesity. And a recent report from the Institute estimated that, in the U.S., 14 percent of deaths from cancer in men and 20 percent of deaths in women were due to overweight and obesity.
Dieli-Conwright and her team recently presented their study’s findings at The Endocrine Society's 93rd Annual Meeting in Boston.
Their research involved participants of the large California Teachers Study who, between 1995 and 2006, received a diagnosis of invasive breast cancer - cancer that has spread beyond the breast ducts. Of the 3,995 women studied, 262 died of breast cancer through 2007, the authors reported in their abstract.
The researchers defined obesity as a body mass index (BMI, in kg/m2) of 30 or higher. The authors obtained BMI, a measure of height and weight, from questionnaires showing each participant's self-reported height and weight at baseline and at age 18. Baseline was the beginning of the study and was near, but necessarily at, diagnosis, according to Dieli-Conwright.
The study’s authors analyzed the mortality risk by estrogen receptor status (whether the hormone estrogen fuels the breast cancer) and found that the relationship between being overweight or obese and dying from the breast cancer depends on whether the breast cancer is hormonally dependent. Experts tell us that women who are obese or overweight tend to have higher levels of circulating estrogen, and thus, increases their chances of the cancer spreading further and more quickly than normal weight women.
“Women who were obese at baseline had a 69 percent higher risk of dying of their breast cancer than did non-obese women,” Dieli-Conwright said. This same increased death risk was present in women who were overweight (BMI of 25 to 29) at age 18.
"What we know now is that there is a strong link between dying from breast cancer and being obese," Dieli-Conwright continued. "And it's not just your BMI near the time you're diagnosed that's important."
Dieli-Conwright emphasized that with the obesity epidemic on the rise, managing and maintaining a healthy weight is crucial to the prevention and survivorship of cancer. And that being overweight early in life can cause great detriment for your chances of breast cancer survival later in life.
Obesity raises breast cancer survivors’ risk of dying from the cancer
http://www.eurekalert.org/pub_releases/2011-06/tes-orb060311.php
National Cancer Institute: Obesity and cancer
http://www.cancer.gov/cancertopics/factsheet/Risk/obesity
Obesity Raises Breast Cancer Survivors' Risk of Dying of the Cancer, Study Finds
http://www.sciencedaily.com/releases/2011/06/110604182014.htm
Reviewed June 8,2011
Edited by Alison Stanton
Bailey Mosier is a freelance journalist living in Winter Park, Florida. She received a Masters of Journalism from Arizona State University, played D-I golf, has been editor of a Scottsdale-based golf magazine and currently contributes to GolfChannel.com. She aims to live an active, healthy lifestyle full of sunshine and smiles.