Background: Clinical studies agree that obesity worsens the prognosis of breast carcinoma in both pre- and postmenopausal women. There is considerable evidence that free estrogen levels are raised in obese women, especially in those with abdominal (visceral) obesity and hyperinsulinemic insulin resistance. It has been postulated that estrogen may synergize with the concomitants of hyperinsulinemia in stimulating breast carcinoma growth. Reduction of estrogen and insulin levels may slow this growth.
Methods: A current clinical trial in the U.S. is examining the effect of dietary fat reduction on recurrence and survival rates after primary treatment of early stage breast carcinoma in postmenopausal women. Recent research suggests that a high fiber/fat ratio in the diet and regular physical exercise may help to reduce estrogen and insulin levels. Regular exercise may also help to maintain long term weight loss.
Results: A second-generation trial is proposed of a high fiber, low fat diet associated with regular physical exercise in women with early breast carcinoma. Changes in circulating levels of estrogen and insulin will be monitored in relation to timing of tumor recurrence and second primary breast carcinoma rates. Weight and fat distribution will be monitored in relation to measurements of dietary compliance.
Conclusions: Breast carcinoma patients wishing to change their lifestyle are likely to benefit from a higher dietary fiber/fat ratio combined with regular physical exercise. If the trial shows an improved prognosis from intervention correlated with changes in biomarkers, a similar trial model could be used to identify specific fiber supplements, micronutrients, and exercise regimens that may improve survival rates in patients with breast carcinoma.