Abstract S5-08: Final survival analysis from the randomized Women's Intervention Nutrition Study (WINS) evaluating dietary intervention as adjuvant breast cancer therapy

Abstract

Abstract Between 1994 and 2001, 2,437 women between 48-79 years of age with early-stage breast cancer (73% node negative, 79% estrogen receptor positive, 70% = or < 2 cm) receiving standard cancer management (endocrine therapy +/- chemotherapy if hormone receptor positive or chemotherapy if hormone receptor negative plus radiation therapy if clinically indicated) were randomized, within 6 months of diagnosis, to a dietary intervention or control group from 39 US centers participating in the Women’s Intervention Nutrition Study (WINS). The dietary intervention, targeting fat intake reduction while maintaining nutritional adequacy, was initiated during 8 biweekly individual counseling sessions by centrally trained registered dieticians implementing a previously developed low-fat eating plan with subsequent every 3 month dietician contacts. During 5 years (median) intervention, fat intake was significantly reduced (from 29.2% to 20.3% of calories, P< 0.0001) as was body weight (-2.7 kg, P=0.005) in the dietary intervention group but not in the control group. Relapse-free survival, the primary study endpoint, was favorably impacted in the dietary intervention compared to the control group (9.8% vs 12.4% with events, respectively, HR 0.78 95% CI 0.60-0.98, P = 0.03 from adjusted Cox model) (J Natl Cancer Inst 2006:98;1767). Exploratory analyses suggested a greater dietary effect on women with hormone receptor negative cancers.When intervention ended after 5 years median follow-up with a total of 171 deaths, there were somewhat fewer deaths in the intervention group (6.6% vs 7.3%, HR 0.89 95% CI 0.65-1.21). In the last WINS update, based on national death registry information after 8.1 years median follow-up with a total of 251deaths, while there were fewer deaths in the intervention compared to the control group (9.1% vs 11.1%), the difference was again not statistically significant (HR 0.78 95% CI 0.59-1.03) (J Clin Oncol 2008:26;522). With this as background, the primary study objective is to determine, with updated survival information after now 15 years median follow-up, whether a lifestyle intervention targeting fat intake reduction associated with significant weight loss will improve overall survival in early stage breast cancer patients receiving standard breast cancer management. Information on survival is being obtained regarding the status of the 2,081 WINS study participants last known to be alive using the National Death Registry identified through DOBsearch.com. It is anticipated that there will now be a total of approximately 430 deaths in the trial. The new information will be incorporated in updated survival analyses, using time-to-event methods based on intention-to-treat principles, for the overall population and for subgroups of interest. Results will be presented as a late breaking abstract. Citation Format: Rowan T Chlebowski, George L Blackburn. Final survival analysis from the randomized Women's Intervention Nutrition Study (WINS) evaluating dietary intervention as adjuvant breast cancer therapy [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S5-08.