Background Five years of statin therapy lowers low-density lipoprotein (LDL) cholesterol substantially and, over a 5-year period, results in reductions in the incidence of cardiovascular events. The Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) trial has raised the hypothesis that adding ezetimibe to statin therapy for larger LDL cholesterol reductions might increase the incidence of cancer.

Methods We compared the results of a hypothesis-generating analysis of the incidence of cancer in the SEAS trial of ezetimibe plus simvastatin in 1873 patients (mean follow-up after ezetimibe or matching placebo was begun, 4.1 years) with a hypothesis-testing analysis of cancer data from the two large ongoing trials of this regimen: the Study of Heart and Renal Protection with 9264 patients (mean follow-up, 2.7 years) and the Improved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) , currently with 11,353 patients (mean follow-up, 1.0 year).

Results In the SEAS trial, assignment to ezetimibe was associated with an increase in any new onset of cancer (101 patients in the active-treatment group vs. 65 in the control group) from several cancer sites. In SHARP and IMPROVE-IT combined, there was no overall excess of cancer (313 active-treatment vs. 326 control; risk ratio, 0.96; 95% confidence interval, 0.82 to 1.12; P=0.61) and no significant excess at any particular site. Among patients assigned to ezetimibe, there were more, albeit not significantly more, deaths from cancer (97, vs. 72 in the control group; P=0.07), but there were also fewer, although not significantly fewer, other cases of cancer (216, vs. 254 in the control group; P=0.08). There was no evidence of a trend in the risk ratio for incidence of or death from cancer with increasing duration of follow-up.

Conclusions The available results from these three trials do not provide credible evidence of any adverse effect of ezetimibe on rates of cancer. Follow-up of longer duration will permit the balance of risks and benefits to be determined more reliably.

www.nejm.org September 2, 2008 (10.1056/NEJMsa0806603)