The study of the relationship between dietary intake of vitamin E and the risk of breast cancer has not yielded definite conclusions with respect to causality, possibly due to methodological issues inherent to nutritional epidemiology. To avoid the pitfalls of dietary recalls, a-tocopherol content of adipose tissue was used as a biochemical indicator of long-term dietary intake of vitamin E. a-tocopherol and hydroperoxides were measured in breast adipose tissue obtained at the time of diagnosis from 70 patients with early breast cancer. Thirty women with non-malignant breast tumors sewed as control. Lipid peroxidation was monitored by quantifying conjugated dienes spectrophotometrically and by assaying hydroperoxides with an iodometric method; a-tocopherol was measured by HPLC associated with fluorescence detection. Mean a-tocopherol value in breast adipose tissue was significantly lower in breast cancer patients than in control patients, whereas the hydroperoxide content was significantly higher in cancer patients than in controls. The a-tocopherol concentration in adipose tissue was not correlated with the clinical status of the patients with respect to age, menopausal status or body mass index. We conclude from this pilot study that breast cancer is associated with a low content of a-tocopherol in breast adipose tissue, and with an altered lipid oxidation pattern, which might be related to a low antioxidant status.