Obesity and weight gain have long been risk factors associated with death from breast cancer. In a recent study published in the journal Cancer, a multi-institutional team of researchers, headed by Virginia Kaklamani, M.D., from UT Health San Antonio, focused on the factors that affect weight gain in women diagnosed with breast cancer.
The researchers determined that women younger than age 60 diagnosed with breast cancer who have a genetic risk factor for obesity have a higher risk for gaining weight and therefore should begin a weight-loss program to increase their chance for survival.
The study was conducted from May 2009 to August 2014 with 393 women at the Robert H. Lurie Comprehensive Cancer Center at Northwestern University, where Dr. Kaklamani was a faculty member before joining UT Health in November 2014.
“Obesity has been identified as a risk factor in developing breast cancer, in breast cancer recurrence and with a greater chance of dying from breast cancer,” said Dr. Kaklamani, a hematologist/oncologist and leader of the breast cancer program at the UT Health Cancer Center.
“We think this is due to obesity increasing the body’s production of estrogen and inflammation, and the risk for developing metabolic syndrome,” she said. (Metabolic syndrome is a group of factors that raise the risk for such conditions as heart disease, diabetes and stroke.)
Previous studies have shown that women with breast cancer are more likely to gain weight after diagnosis than women without the disease. Several other studies had examined various factors, including the patient’s receipt of chemotherapy vs. tamoxifen, age at diagnosis, tumor characteristics, menopausal status and the role of genetic factors in relation to cancer diagnosis and weight gain.
“All these various factors were analyzed using data from past studies, but there have been no studies done that examined these factors in newly diagnosed breast cancer patients where the women could be followed,” Dr. Kaklamani said.
“The objective of our study was to evaluate the role of demographic, treatment-related, metabolic, genetic and lifestyle-related factors in breast cancer-related weight gain,” she said.
Blood samples were taken to identify risk factors for obesity and insulin resistance. A statistical analysis was conducted to analyze various factors related to the patients’ demographic, clinical and treatment characteristics. The patients’ body mass index was taken at the beginning of the study and at six months, 12 months, 18 months and 24 months to measure weight gain or loss.
Results showed that after six months, 29.2 percent of women had gained 3.56 pounds; after 12 months, 37.2 percent of women had gained 3.97 pounds; after 18 months, 46.2 percent had gained 4.64 pounds; and after 24 months, 50.3 percent had gained 4.56 pounds. Weight gains were more common among patients younger than 60 years of age.
“Our take-home message is this: Several factors including a patient’s age and their genetic makeup are implicated in weight gain during breast cancer treatment. This is important because obesity is a risk factor for recurrence,” Dr. Kaklamani said. “Also some treatments don’t work as well in obese patients and obesity also raises the chances for women to develop other chronic diseases. Our recommendation is that all women who are younger than age 60 when they are diagnosed with breast cancer and who have a genetic risk factor for obesity should lose weight to prevent recurrence. I am now recommending that for my patients.”