Dietary fat reduction in postmenopausal women with primary breast cancer: Phase III Women's Intervention Nutrition Study (WINS)

Authors: R. T. Chlebowski, G. L. Blackburn, R. E. Elashoff, C. Thomson, M. T. Goodman, A. Shapiro, A. E. Giuliano, N. Karanja, M. K. Hoy, D. W. Nixon, The WINS Investigators


Background: Despite preclinical and observational studies suggesting benefit, dietary fat influence on breast cancer outcomes has been controversial.

Methods: We conducted a randomized trial to test whether an intensive dietary intervention designed to reduce dietary fat intake was effective in influencing relapse-free survival in postmenopausal women with primary breast cancer. A total of 2,437 women with early stage resected breast cancer, 48-79 years old, were randomized within 365 days from surgery in a 40:60 ratio to dietary intervention or control groups at 37 U.S. sites. All received standard breast cancer management: mastectomy or lumpectomy plus radiation; tamoxifen for ER positive, protocol-defined chemotherapy for ER negative and optional chemotherapy for ER positive cases. The dietary intervention included eight bi-weekly individual counseling sessions conducted by centrally trained nutritionists who provided ongoing contacts throughout.

Results: Patient characteristics and recurrence risk factors were balanced. Dietary fat intake reduction was greater in the dietary group (fat gram intake/day at 12 months, 33.3 + 16.7, mean + standard deviation (SD) versus 51.3 + 24.4 in controls, respectively, p<0.001). After 60 months median follow-up, the 277 reported relapse events are outlined below by treatment group and receptor status.

Conclusions: Life-style intervention resulting in dietary fat intake reduction may improve the relapse-free survival of postmenopausal breast cancer patients.