Serum lipids and outcome of early-stage breast cancer: Results of a prospective cohort study

Purpose. The prognosis of women with early-stage breast cancer is influenced by insulin and body mass index (BMI). High levels of serum insulin and obesity often coexist with dyslipidemia in the insulin resistance syndrome (IRS), but the contribution of lipids to breast cancer outcome is unclear. Here, we examine whether serum levels of total cholesterol (TC) and triglycerides (TG) influence breast cancer outcome. Patients and methods. A cohort of 520 women without known hyperlipidemia or diabetes, with stage T1-T3, N0-N1, M0 breast cancer, was assembled from July 1989 to June 1996. Fasting blood was collected at baseline. Subjects were followed prospectively, for recurrence (local, regional, distant) and death. Cox models were used to calculate the prognostic effect of TC and TG levels. Two-sided significance levels were set at 0.025. Results. TC was correlated with age (Spearman's r = 0.44) and low tumor grade (p = 0.01), while TG was correlated with insulin (r = 0.43) and BMI (r = 0.45). At a median follow-up of 8.7 years, TC and TG were not associated with breast cancer recurrence or death before of after adjustment for age, tumor-related variables, BMI or fasting insulin levels. In multivariate analysis adjusting for age, tumor-related variables and BMI, a trend towards an adverse effect of TC on disease recurrence was seen (HR recurrence = 1.62 for the 4th versus. 1st quartile, 2-sided p = 0.03). Conclusions. Fasting TG was not associated with outcome. A trend towards risk of recurrence was seen with higher TC in multivariate analysis. This potential association should be explored in future studies.