(CBS News) Obesity is already linked to diabetes and heart disease. A study out Monday shows that breast cancer patients who are obese face a greater risk that their cancer will return.
When 65-year-old Gail Brown was diagnosed with breast cancer, she had the standard treatment: surgery, chemotherapy and radiation. Then she tried something on a hunch.
"I had heard that obesity can bring on breast cancer," Brown told CBS News. "I said, well I'd better do something about this."
That was in 2007, when she weighed 193 pounds. Since then, Brown has lost 30 pounds.
"I'm very proud of her," said her doctor, Dr. Joseph Sparano of the Montefiore Einstein Center for Cancer Care.
Sparano is also the lead author of a new study that looked at outcomes in patients with breast cancer. For women receiving the most up-to-date treatment, being obese increased the risk of recurrence by 24 percent and death by 37 percent. The increased risk was limited to women whose tumors were fueled by estrogen. Levels of that hormone may be boosted by an enzyme in fatty tissue.
"It could be related to higher hormone levels, higher insulin levels, or inflammation., which can drive the risk of recurrence," Sparano said.
The study also showed an increased risk not just for obese women, but also for those who were simply overweight.
"The take home message for women with breast cancer is that paying attention to diet, exercise and weight is important, and this can have not only a short term, but a long lasting effect," Brown said.
It's not just recurrence of breast cancer that has been linked to being overweight. The odds of getting cancer in the esophagus, colon, kidney, pancreas and uterus are all increased with obesity.