Dietary fat and breast cancer survival: a systematic review and meta-analysis

Abstract

Background and objectives: A positive association between dietary fat and breast cancer risk has been previously reported but its influence upon survival is unclear. As the number of breast cancer survivors increases worldwide, the aim of this review and meta-analysis is to critically appraise the published literature and conduct meta-analyses to clarify the association between dietary fat and breast cancer survival. Methods: Articles published up to March 2011 that examined dietary fat and breast cancer recurrence/survival were identified from searches in MEDLINE and EMBASE. Metaanalyses were conducted in which we evaluated the risk of allcause or breast cancer specific death in women in the highest compared with the lowest categories of intake and per 20 gram increase in total and saturated fat intake (g/day). Multivariable adjusted hazard ratios (HR) and 95% CIs from individual studies were weighted and combined using a random-effects model to produce a pooled estimate. Results: Fifteen prospective cohort studies investigating total fat and/or saturated fat intake (g/day) and breast cancer mortality were included. There was no difference in risk of breast cancer specific death (n=6; HR=1.14; 95% CI: 0.86, 1.52; P=0.34) or all cause death (n=4; HR=1.73; 95% CI: 0.82, 3.6; P=0.15) for women in the highest versus lowest category of total fat intake. Breast cancer specific death (n=5; HR=1.63; 95% CI: 1.19, 2.24; P<0.01) was however higher for women in the highest versus lowest category of saturated fat intake. No trends were observed per linear (20 gram) increase in intake of total or saturated fat. Conclusions: The results of this systematic review and meta- analysis suggest that a lower saturated fat intake is associated with a lower risk of breast cancer death. Modification of dietary intake, to reduce saturated fat intake may therefore be warranted.