University of Virginia Health System

Study Shows Concern for Obese Breast Cancer Patients

Women who are overweight or obese when diagnosed as having locally advanced breast cancer face a higher chance of recurrence than either normal or underweight patients, a new study shows.

The researchers also found that obese patients are more likely than overweight, normal or underweight patients to be diagnosed as having a rare, aggressive, and deadly form of locally advanced breast cancer known as inflammatory breast cancer (IBC).

"We already know that obesity is a risk factor for many diseases," says study senior author Dr. Massimo Cristofanilli of the M.D. Anderson Cancer Center.

"Now we're showing that women who are obese or overweight essentially face a higher risk for getting a more aggressive form of breast cancer, and progress faster and die faster from their disease," says Cristofanilli.

But two experts - including one from the University of Virginia Health System - believe further studies are needed to better grasp the link between obesity and the progression of breast cancer. 

Two-Thirds in Study Overweight or Obese

Cancer that has spread to nearby tissue or lymph nodes, called locally advanced breast cancer (LABC), accounts for about 5 percent of all breast cancers in the U.S.

In medically underserved parts of the country and the developing world, about half of all breast cancer cases are locally advanced breast cancer.

The even more lethal inflammatory breast disease form of breast cancer strikes between 1 percent and 2 percent of U.S. breast cancer patients.

Noting that 6 in 10 Americans are obese or overweight, Cristofanilli explored possible weight-cancer connections by analyzing data on 606 women who had received similar care for stage III locally advanced breast cancer at M.D. Anderson between 1974 and 2000.

Records of body mass index (BMI) revealed that two-thirds of the patients were either overweight or obese at diagnosis.

Slightly more than 80 percent of the patients had standard locally advanced breast cancer, while 18 percent had the more deadly inflammatory breast cancer.

Comparing weight records with disease statistics, the researchers found that a greater proportion of obese patients were diagnosed as having inflammatory breast cancer compared with overweight or normal weight or underweight patients.

Among all patients with locally advanced breast cancer, overweight or obese women were more likely to have a higher grade of breast cancer at diagnosis, followed by more disease recurrence and shorter survival times.

Cristofanilli notes BMI status was only tracked at diagnosis, not during subsequent treatment. Still, they conclude that obese and overweight women coping with locally advanced breast cancer could benefit from the inclusion of a dietary component in their treatment regimen.

"Obesity is a major issue for our society, and it raises the possibility that perhaps if we reduce excess weight, we might reduce the incidence of breast cancer in the first place," says  Cristofanilli. "And for those already diagnosed, lifestyle modification and weight control - and probably more aggressive follow-up - might be needed in addition to chemotherapy and other standard treatments."

More Study Needed to Understand Link

Dr. Harold J. Burstein of the Dana-Farber Cancer Institute in Boston cautions that the evidence suggesting a link between obesity and poor breast cancer outcomes needs more study.

"There's a lot of suggestive data, but there's nothing that's absolutely definitive," he says. "That is not to say that there is anything to suggest that it is risky for breast cancer patients to make an effort to maintain their weight through food control and exercise. And it can certainly help strengthen bones and lower the risk for diabetes and heart disease, which is all the better. But it really must be said that there are women who torment themselves if they are obese at diagnosis or gain weight afterwards, because they believe they are jeopardizing their outcome."

"Yet the honest assessment is that we don't really understand yet whether there is a relationship between obesity and breast cancer outcomes, or how strong the relationship is," he says.

Richard Santen, M.D., Professor of Medicine at the University of Virginia Health System, says the study has a significant flaw: no data on hormone receptor status.

"It is known that obese women have a higher level of estrogen production from the aromatase enzyme than do thin women. This would provide a very plausible explanation for the worse prognosis in breast cancer. The more the body weight, the higher the estrogen production and the more rapid the growth of the tumor," Santen says. "However, this would only affect women [who are] hormone receptor positive. Without information of receptor status, this remains an interesting clinical observation but without an underlying biologic explanation."

"It is of interest that there is a higher incidence of inflammatory breast cancer in the obese, but again there is no hypothesis to explain this," he adds. "The relationship between weight and prognosis does not prove that losing weight will improve [a patient's] prognosis and another study needs to be done to examine this issue."

To read a patient story, get additional information on breast cancer treatment or learn about UVA's Breast Care Program, visit www.uvahealth.com. 

UVA also offers a free, confidential risk assesment through the region's only High Risk Care program to determine if you have a higher-than-normal personal risk of developing breast or ovarian cancer. This free service is particularly encouraged for women with a strong family history of breast or ovarian cancer. To arrange the free screening, call 434-982-0808.

Women can learn more about their unique risks for heart disease - and how to better manage those risks - through Live Red, a new UVA heart-health initiative. You'll learn how heart attack symptoms can be different for women than for men, and you can take an online risk assessment to learn your personal heart disease risk factors.

There, you can sign up for Club Red, our free heart-healthy club for women. Benefits include tips from UVA healthcare providers and a gift package to help you live red in style.

Always consult your physician for more information.