Introduction
Tamoxifen is a selective estrogen receptor modulator widely used in the treatment of breast cancer. Tamoxifen therapy is associated with lower circulating low-density lipoprotein cholesterol and increased triglycerides, but its effects on other lipids are less well studied.
Aims
We aimed to investigate the effect of tamoxifen on circulating concentrations of lipoprotein(a) [Lp(a)] through a meta-analysis of available randomized controlled trials (RCTs) and observational studies.
Methods
This study was registered in the PROSPERO data base (CRD42016036890). Scopus, MEDLINE and EMBASE were searched from inception until 22 March 2016 to identify studies investigating the effect of tamoxifen on Lp(a) values in humans. Meta-analysis was performed using an inverse variance-weighted, random-effects model with standardized mean difference (SMD) as the effect size estimate.
Results
Meta-analysis of five studies with 215 participants suggested a statistically significant reduction of Lp(a) levels following tamoxifen treatment (SMD −0.41, 95% confidence interval −0.68 to −0.14, p = 0.003). This effect was robust in the sensitivity analysis.
Conclusions
Meta-analysis suggested a statistically significant reduction of Lp(a) levels following tamoxifen treatment. Further well-designed trials are required to validate these results.
Maciej Banach, Maria-Corina Serban, Camelia Gurban, Sorin Ursoniu and Amirhossein Sahebkar conceived and designed the work, and contributed to the drafting of the manuscript. Maria-Corina Serban, Peter Penson and Sorin Ursoniu performed the searches and extracted data. Amirhossein Sahebkar performed the statistical analysis. Peter Penson, Peter P. Toth, Steven R. Jones, Giuseppe Lippi, Kazuhiko Kotani, Karam Kostner, Manfredi Rizzo, Jacek Rysz and Maciej Banach contributed to the interpretation of the work and revised the manuscript critically for important intellectual content. All authors have approved the final manuscript and agree to be held accountable for all aspects of the work.
This meta-analysis was written independently; no company or institution supported it financially. Dr. Penson owns four shares in AstraZeneca PLC, which he inherited during 2015. Dr. Toth is a member of the speakers’ bureau for Amarin, Amgen, Merck, and Regeneron-Sanofi; and a consultant to Amarin, Amgen, AstraZeneca, Kowa, Merck, and Regeneron-Sanofi. No professional writer was involved in the preparation of this meta-analysis.