Study Shows Concern for Obese Breast Cancer Patients

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

In addition, overweight and obese patients have a shorter life expectancy, according to a report in the medical journal Clinical Cancer Research.

The researchers also found that obese patients are more likely than overweight, normal, or underweight patients to be diagnosed with 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, at the MD Anderson Cancer Center in Houston, Texas.

"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 Dr. Cristofanilli.

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 US.

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 US breast cancer patients.

Noting that six in 10 Americans are obese or overweight, Dr. 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 MD 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 with inflammatory breast cancer compared with either overweight or normal/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.

Dr. 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 Dr. 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, at 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," notes Dr. Burstein.

"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.

Always consult your physician for more information.

Online Resources

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American Cancer Society

Clinical Cancer Research — Prognostic Value of Body Mass Index in Locally Advanced Breast Cancer

Department of Defense — Breast Cancer Program

National Breast Cancer Coalition

National Cancer Institute (NCI)

People Living With Cancer

Susan G. Komen For the Cure