Vitamin A and Breast Cancer Survival: A Systematic Review and Meta-analysis

Background

The association between vitamin A intake and breast cancer survival has been inconsistent. We conducted a systemic review and meta-analysis to summarize the results on the association between dietary or supplement vitamin A and its derivatives and breast cancer-specific survival and overall survival (OS).

Materials and Methods

A comprehensive search of PubMed and EMBASE was performed from inception to January 31, 2018. The summary hazard ratios and 95% confidence intervals were estimated using a random effects model.

Results

Ten studies (8 cohort, 1 clinical trial, and 1 of pooled studies), with 19,450 breast cancer cases, were included in the meta-analysis. The dietary intake of β-carotene was significantly associated with improved breast cancer OS, with a summary hazard ratio of 0.70 (95% confidence interval, 0.50-0.99; I² = 37.5%) for the highest versus lowest intake and 0.93 (95% confidence interval, 0.88-0.99; I² = 38.7%) per 1200 μg/day increment of intake when assessing diet before diagnosis. Meta-regression analysis showed that adjustment for body mass index was a modified factor for the association between the intake of β-carotene and breast cancer OS (P = .013). However, the intake of other vitamin A derivatives (eg, α-carotene, β-cryptoxanthin, lycopene, retinol, lutein) had no effect on breast cancer prognosis when assessing diet before and after the diagnosis.

Conclusion

Our findings suggest limited evidence for the significantly inverse association between the prediagnosis dietary intake of β-carotene and OS among women with breast cancer. However, the intake of other vitamin A derivatives was not significantly associated with survival.