Women with early-stage hormone-negative breast cancer (negative for both estrogen and progesterone) who reduced their dietary fat intake for five years following a diagnosis had a 56 percent reduction in death from all causes in comparison to those who did not modify their diets, according to 15 years of data as part of the Women’s Intervention Nutrition Study (WINS) presented at the 2014 San Antonio Breast Cancer Symposium.
This was an even better response than was seen in the original WINS report, published in 2006, after five years of follow up
“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 said Rowan Chlebowski, MD, PhD, medical oncologist at the Los Angeles Biomedical Research Institute at the Harbor-UCLA Medical Center.
"Our findings suggest that if a lifestyle intervention is to have long-term influence on clinical outcome, it must be a lifelong change rather than be a short-term alteration."
The WINS was a randomized trial of 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 six months from diagnosis, all women were randomly assigned either to a dietary intervention group (975 patients, of whom 205 had ER negative cancer, and 147 had ER/PR-negative cancer) or to a control group (1,462 patients, of whom 273 had ER-negative cancer, and 215 had ER/PR-negative cancer).
Women in the study group were given a fat gram goal by centrally trained, registered dieticians implementing a low-fat eating plan, explained Chlebowski. The women underwent eight biweekly individual counseling sessions with subsequent contacts every three months. They self-monitored their fat/gram intake using a “keeping score” book. Fat intake was externally monitored by unannounced 24-hour telephone recalls performed annually.
The study group kept fat intake at about 20 percent of daily diet. This meant eating more vegetables and fruit. Women who did best emphasized healthy fats such as olive oil, fish and avocados and also added exercise to their regimen.
After five years of dietary intervention, fat calories were lowered by 9.2 percent and body weight
was lowered by nearly 6 pounds in the intervention group, compared with the control group.