According to the researchers, high total and saturated fat intake were associated with greater risk of estrogen receptor- and progesterone receptor-positive (ER+PR+) breast cancer (BC), and human epidermal growth factor 2 receptor-negative (HER2-) disease.
Published data from epidemiological and case-control studies on the association between high fat intake and BC risk have been conflicting, which may be attributable to difficulties obtaining accurate information on fat intake and because of limited heterogeneity of intake within a specific geographic area from which the study cohorts live.
Furthermore, BC is now classified clinically into subtypes by ER, PR, and HER2 expression status and each subtype has its own prognosis and set of risk factors, which may also contribute to the inconsistencies in the published reports on this relationship.
Sabina Sieri, Ph.D., from the Epidemiology and Prevention Unit of the Department of Preventive and Predictive Medicine at Fondazione IRCCS Istituto Nazionale Dei Tumori in Milan Italy, and colleagues prospectively analyzed data from 10,062 BC patients from the EPIC study with 11.5 years of follow-up.
The authors report high total and saturated fat intake were associated with greater risk of ER+PR+ BC. High saturated fat intake was also associated with greater risk of HER2- disease.
The authors conclude, "a high-fat diet increases BC risk and, most conspicuously, that high saturated fat intake increases risk of receptor-positive disease, suggesting saturated fat involvement in the etiology of receptor-positive BC."
The study is published in the Journal of the National Cancer Institute.