UICC World Cancer Congress 2006

Objective: Prospective studies show that high serum levels of androgens and estrogens are associated with increased incidence of postmenopausal breast cancer. Metabolic factors such as high plasma insulin, glucose and triglycerides, blood pressure, waist circumference, and low HDL cholesterol may also predict breast cancer risk. There is increasing evidence that these same factors effect breast cancer prognosis The aim of the present study is to analyse their prognostic value in postmenopausal breast cancer patients and the effect of a comprehensive dietary modification aiming at reducing insulin levels.

Methods: 110 breast cancer patients without clinical recurrence followed a low-glycaemic index and low-saturated fat diet for one year, based on Mediterranean and macrobiotic recipes. After 5.5 years of follow-up, 31 patients developed recurrences: distant (16), local (4), or contralateral breast cancer (11). The risk of adverse events in relation to hormone level at baseline and after the intervention was examined by Cox proportional hazard modelling, adjusting for hormone receptor status and stage at diagnosis.

Results: High serum testosterone levels and the presence of metabolic syndrome at baseline were associated with a significantly higher recurrence rate. The adjusted hazard ratio of recurrences among women with metabolic syndrome and testosterone levels higher than 0.40 ng/ml (median value) was 6.7 (95% CI 2.3-19.8) compared with women without metabolic syndrome and testosterone levels up to 0.40 ng/ml. The dietary intervention significantly improved the hormonal and metabolic pattern and results suggested that decreasing serum testosterone by dietary intervention can reduce the recurrence rate.