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.
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."
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.
(Our Organization is not responsible for the content of Internet sites.)
As defined by the National Cancer Institute (NCI), stages of breast cancer are:
Carcinoma in situ
Patients with this condition have a 25 percent chance of developing breast cancer in either breast in the next 25 years.
Stage IIA is defined by: no tumor is found in the breast, but cancer is found in one to three axillary lymph nodes, or the cancer is no larger than 2 centimeters (about 1 inch) but has spread to the lymph nodes under the arm (the axillary lymph nodes) or the cancer is between and 5 centimeters (from 1 to 2 inches), but has not spread to the lymph nodes under the arm.
Stage IIB is defined by: the cancer is between 2 and 5 centimeters (1 to 2 inches) and has spread to the lymph nodes under the arm or the cancer is larger than 5 centimeters (larger than 2 inches), but has not spread to the lymph nodes under the arm.
Stage IIIA is defined by: no tumor is found in the breast, but cancer is found in four to nine axillary lymph nodes that are attached to each other or to other structures or the cancer is smaller than 5 centimeters and has spread to the lymph nodes under the arm, and the lymph nodes are attached to each other or to other structures or the cancer is larger than 5 centimeters and has spread to the lymph nodes under the arm.
Stage IIIB is defined by: the cancer has spread to tissues near the breast (skin or chest wall, including the ribs and the muscles in the chest) or the cancer has spread to lymph nodes inside the chest wall along the breast bone or under the arm.
Stage IIIC is defined by: cancer has spread to lymph nodes under the collarbone and near the neck or cancer may have spread to lymph nodes in the breast or underarm and to tissues near the breast.
Inflammatory breast cancer
Always consult your physician for more information.