Office of Health Promotion Research
New UVM College of Medicine Study Emphasizes the Role of Breast Density in Cancer
Release Date: 07-14-2000
by Jennifer Nachbur
A three-year study initiated by a medical student at the University of Vermont (UVM) College of Medicine has bolstered the evidence that the denser a woman's breast tissue, the higher her risk of breast cancer. The study also confirmed that body weight is another powerful risk factor for breast cancer. These findings suggest that both body weight and breast density should be considered when estimating a woman's risk. Fat makes breasts less dense, meaning that heavier women tend to have less-dense breasts and thinner women tend to have denser breasts.
The study will be published in the July 15 issue of the American Cancer Society's journal, Cancer.
This study is the first to verify breast cancer risk with a widely used measure--the American College of Radiology-recommended breast density classifications--instead of less-common measurements favored by researchers. This means that radiologists may be able to help assess a woman's risk when they review patient mammograms. And women may be able to mitigate the risk, since preliminary results from a randomized trial suggest that breast density may be reduced by following a low-fat, high-carbohydrate diet, particularly in women going through menopause.
"The importance of weight and breast tissue density as risk factors for breast carcinoma cannot be overstated, not only because of the strength of their associations with risk but also because they are modifiable," the study authors conclude in their report.
UVM College of Medicine class of 2000 graduate Prudence Lam, M.D., initiated this study, which was the first to analyze risk factors for Vermont women using data from the Vermont Breast Cancer Surveillance System (VBCSS). The Vermont Breast Cancer Surveillance System is a cooperative agreement between the National Cancer Institute (NCI) and UVM to study usage and effectiveness of mammography and to gather data on risk factors.
Lam and her co-authors reviewed VBCSS data from 529 Vermont women with breast cancer and 2,116 women not diagnosed with breast cancer. The study teased apart the separate impacts of body weight and breast density on cancer risk. Women weighing more than 81 kilograms (about 178 pounds) had 2.1 times the risk of cancer compared with those weighing less than 63 kilograms (135 pounds). Compared with women whose breasts were the least dense, those with the most-dense breast tissue had 4.5 times the risk of cancer--and even moderately dense breasts increased risk by 2.3 times.
"Our findings indicate that both body weight and breast density need to be considered together in determining an individual's risk," said Berta Geller, Ed.D., research associate professor in the Office of Health Promotion Research and the department of family practice at UVM's College of Medicine. "For example, a heavier woman who happens to have dense breasts is at an even greater risk than her weight alone suggests."
Most of the women in the study 72 percent were postmenopausal. The study found no increased risk associated with dense breasts among premenopausal women or women taking hormone replacement therapy.
The study was funded through a grant from the NCI. Co-authors of the study include Lam, Geller, Hyman Muss, M.D., associate director of the Vermont Cancer Center and clinical leader in cancer care at UVM/Fletcher Allen and Pamela Vacek, Ph.D., biostatistician, UVM department of medical biostatistics. Lam currently is serving an internal medicine residency at Mt. Auburn Hospital in Cambridge, Mass.
"This is a terrific accomplishment for a medical student," said Geller. "Dr. Lam's desire to approach this research from a public health perspective made her unique. She did the literature review, worked with the study team to complete an analysis of the VBCSS data and wrote the article."
Breast cancer is the most commonly diagnosed cancer and second leading cause of cancer-related deaths in women in the United States, according to Cancer Statistics 2000, published by the journal Cancer.
Last modified September 16 2013 04:11 PM