PHILADELPHIA - Women with breast cancer have more aggressive disease and lower survival rates if they are overweight or obese, according to findings published in the March 15 issue of Clinical Cancer Research, a journal of the American Association for Cancer Research.
"The more obese a patient is, the more aggressive the disease," said Massimo Cristofanilli, MD, associate professor of medicine in the Department of Breast Medical Oncology at The University of Texas M.D. Anderson Cancer Center. "We are learning that the fat tissue may increase inflammation that leads to more aggressive disease."
Cristofanilli and colleagues observed 606 women with locally advanced breast cancer. These women were classified by body mass index into the following three groups: normal/underweight (24.9 or below), overweight (at least 25 but less than 30) or obese (more than 30). Body mass index is calculated by dividing a person's weight by their height.
At five years, overall survival was 56.8 percent among obese women, 56.3 percent among overweight women and 67.4 percent among normal weight women. The 10-year survival rate was 42.7 percent among obese women, 41.8 percent among overweight women and 56.5 percent among normal weight women.
The rate of inflammatory breast cancer, previously shown to have worse outcomes than non-inflammatory breast cancer, among obese women was 45 percent compared with 30 percent in overweight women and only 15 percent in women considered normal weight, researchers found.
Risk of breast cancer recurrence was also higher in obese or overweight women. By five years, 50.8 percent of obese women reported a recurrence compared with 38.5 percent of normal weight women. By 10 years, the rate of recurrence was 58 percent among obese women and 45.4 percent among normal weight women.
"Obesity goes far beyond just how a person looks or any physical strain from carrying around extra weight. Particular attention should be paid to our overweight patients," Cristofanilli said.
Cristofanilli said physicians need to pay close attention to breast cancer patients because commonly used drugs, such as tamoxifen, tend to increase weight gain during treatment.
"We have actually become quite good at managing acute side effects such as nausea in our chemotherapy patients and it goes away within a couple of days," Cristofanilli said.
"Following the nausea, our patients tend to overeat, which further increases their risk of weight gain. We need to implement lifestyle modifications interventions and develop better methods to follow these patients closely."
The study was funded by the Susan G. Komen Foundation, the Nellie B. Connally Fund for Breast Cancer Research and the Inflammatory Breast Cancer Research Group.
The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, AACR is the world's oldest and largest professional organization dedicated to advancing cancer research. The membership includes nearly 27,000 basic, translational, and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 70 other countries. AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants. The AACR Annual Meeting attracts more than 17,000 participants who share the latest discoveries and developments in the field. Special Conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment, and patient care. AACR publishes five major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention. Its most recent publication and its sixth major journal, Cancer Prevention Research, is the only journal worldwide dedicated exclusively to cancer prevention, from preclinical research to clinical trials. The AACR also publishes CR, a magazine for cancer survivors, patient advocates, their families, physicians, and scientists. CR provides a forum for sharing essential, evidence-based information and perspectives on progress in cancer research, survivorship, and advocacy.