According to results recently presented at the 2006 annual San Antonio Breast Cancer Symposium, a low-fat diet appears to significantly reduce the risk of cancer recurrence among women with estrogen receptor-negative breast cancer.
Environmental and lifestyle factors-such as smoking, physical activity, and diet-are believed to play an important role in the development of many types of cancer and may also influence cancer prognosis. Studies continue to evaluate the links between these factors and cancer, with the goal of reducing cancer risk or improving cancer outcomes.
Results from a large clinical trial known as the Women’s Intervention Nutrition Study (WINS) provide information about the effects of a low-fat diet on risk of recurrence among women with breast cancer.
This study included over 2,400 women who had undergone surgery for early breast cancer. Women were assigned to continue with a normal diet or to eat a low-fat diet in which fat provided 20% or less of total calories.
Women have now been followed for nearly six years.
- Women who ate the low-fat diet lost an average of 5–6 pounds.
- Among all women survival without cancer recurrence was 22% better in women who ate the low-fat diet, but this result did not meet the criteria for statistical significance. This means that the result could have occurred by chance alone.
- When women with estrogen receptor-positive and estrogen receptor-negative breast cancer were analyzed separately, a protective effect of a low-fat diet was observed among women with estrogen receptor-negative breast cancer but not among women with estrogen receptor-positive breast cancer. Among women with estrogen receptor-negative breast cancer, a low-fat diet cut the risk of recurrence in half.
- A low-fat diet also improved overall survival among women with estrogen receptor-negative breast cancer.
The researchers concluded that a low-fat diet appears to improve recurrence-free and overall survival among patients with estrogen receptor-negative breast cancer. The explanation for this finding is still uncertain-it could be the result of either the reduction in dietary fat or the weight loss that accompanied the low-fat diet.
During the question period following the presentation, it was noted that results of this magnitude are comparable to the use of standard treatment. Dietary changes may provide important benefits for certain subsets of breast cancer patients.
Reference: Chlebowski R, Blackburn G, Elashoff R, et al. Oral presentation from the 2006 annual San Antonio Breast Cancer Symposium. Mature analysis from the women's intervention nutrition study (WINS) evaluating dietary fat reduction and breast cancer outcome. December 16, 2006. Abstract #32.