What You Need to Know: Patients with breast cancer who reduced their dietary fat intake for 5 years after a diagnosis of hormone-unrelated early-stage breast cancer had signficantly reduced all-cause death rates, according to data from the Women’s Intervention Nutrition Study (WINS) presented at the 2014 San Antonio Breast Cancer Symposium.
The Study: For WINS, a randomized trial, Dr. Chlebowski and colleagues recruited 2,437 women ages 48 to 79 years with early-stage breast cancer receiving standard-of-care treatments at 39 centers in the United States. Of them, 1,597 had ER-positive breast cancer, 478 had ER-negative breast cancer, and 362 had ER/PR-negative breast cancer. Within 6 months of diagnosis, subjects were randomly assigned either to a dietary intervention group (n=975; 205 with negative cancer, and 147 ER/PR-negative cancer) or to a control group (n=1,462; 273 ER-negative cancer, and 215 ER/PR-negative cancer).
The dietary intervention was centered on a goal of lowering fat intake for 5 years while maintaining nutritional adequacy. Centrally trained, registered dieticians implementing a low-fat eating plan, gve women in the intervention group a fat gram goal, and the women underwent 8 biweekly individual counseling sessions with subsequent contacts every 3 months. Subjects also self-monitored their fat/gram intake using a “keeping score” book. Fat intake was externally monitored by unannounced annual 24-hour telephone recalls done.
“The current findings with respect to long-term influence of dietary lifestyle intervention on overall survival are mixed, but of potential importance,” said Rowan Chlebowski, MD, PhD, medical oncologist at the Los Angeles Biomedical Research Institute at the Harbor-UCLA Medical Center. “In a prior report of WINS after 5-years’ follow-up, relapse events were 24% lower in the intervention group. In the current report, the intervention influence on long-term survival was examined. Overall, while the death rate was somewhat lower in the intervention group compared with control group (13.6% versus 17%, respectively), the difference was not statistically significant. However, in exploratory subgroup analyses, in women with estrogen receptor [ER]-negative cancers, a 36 percent, statistically significant reduction in deaths was seen in women in the intervention group,” said Dr. Chlebowski.
- In women with cancers that were both ER- and progesterone receptor [PR]-negative, the reduction was even more significant (56%), Dr. Chlebowski added.
- After 5 years of dietary intervention, researchers found that fat calories were lowered by 9.2% and body weight was lowered by nearly 6 pounds in the intervention group, compared with the control group.
“HER2 evaluation was not available when this study was conducted, but it is likely that a substantial number of ER/PR-negative breast cancers were also negative for HER2, making them triple-negative breast cancers, which generally have a poor prognosis,” said Dr. Chlebowski. “The signal that perhaps a lifestyle intervention targeting dietary fat intake associated with weight loss could substantially increase the chances of survival for a woman with triple-negative breast cancer could influence this group of patients.”
My Take: It is wonderful that we have an increasing body of evidence that dietary manipulation may lower your risk of recurrence. The drop is not small: It is more than half for those whose tumors are not driven by either estrogen or progesterone. In addition, you may lower your risk of heart attack, stroke, other cancers, and a myriad of other medical problems. Researchers in this study supported the dietary intervention for a median of 5 years. Aim for a lifelong change rather than be a short-term alteration in your diet. I’m Dr. Michael Hunter.
Reference: 37th San Antonio Breast Cancer Symposium (December, 2014); San Antonio, TX