Diet and prognosis of breast cancer

Abstract

The relationship between the occurrence of breast cancer and dietary intake, in particular a high‐fat diet, has attracted much attention in recent years. In addition, the prognosis of breast cancer patients on the basis of dietary intake is also an interesting subject. The present study utilized breast cancer patients whose dietary intake was carefully assessed about one decade previously in a case‐control study to determine whether dietary intake was indeed related to the patients’ prognosis. The study included 212 patients who underwent a surgical operation between 1975 and 1978. They were followed‐up until 1987, and a total of 47 breast cancer deaths were certified. The 5‐ and 10‐year relative survival rates were 78.5% and 75.3%, respectively. The older patients tended to ingest smaller amounts of all nutrients, except animal fat from fish. Height was significantly correlated with total animal protein intake, whereas there was no significant correlation between body mass index and intake of any nutrient. Although the age‐adjusted mean values of the nutrient intakes, other than vegetable fat, decreased with advancing stage, the differences were statistically insignificant. The results of multivariate analyses, in which some confounding factors (e.g., clinical stage) were adjusted using a proportional hazards model, showed that all hazards ratios in each nutrient were close to unity, and no dose‐response relationship was seen. The present investigation did not provide any support for the hypothesis that a high‐fat diet is a survival determinant for breast cancer patients. It should be qualified, however, that these negative results were obtained from the study on Japanese women, who develop breast cancer at an earlier age and consume relatively small amounts of fat.