Tamoxifen linked to 82% increase in strokes

More than 250,000 women in the United States are diagnosed with breast cancer each year and many are given the prescription tamoxifen. Recent studies, however, show that the drug Tamoxifen increases the risk of thromboembolism (a blood clot that has traveled from its site of origin to another vessel and therefore can increase the risk of stroke as much as 82%.

The research was published in Neurology, the scientific journal of the American Academy of Neurology (AAN). Researchers from Duke University Medical Center conducted a systematic review of all clinical trials of tamoxifen published since 1980 using MEDLINE.

Nine trials met their inclusion criteria, with 39,601 total subjects enrolled, 19,954 of whom were randomized to tamoxifen. Six of the trials specifically reported ischemic stroke events. All trials used a standard dose of tamoxifen (20 mg daily).

“With tamoxifen, we found the frequency of all strokes was 1.06% and for ischemic stroke was 0.71%, versus 0.39% with controls,” reported study author Cheryl Bushnell, MD, MHS. The risk of ischemic stroke increased by 82% and risk of all strokes by 29% in women randomized to tamoxifen versus placebo or other therapies.

Despite the uncontestable numbers reported in the study, the AAN distributed a press release saying the increase in risk was “slight,” and listing the supposed benefits of the drug before mentioning the research results.

SOURCE: “Risk of ischemic stroke with tamoxifen treatment for breast cancer: A meta-analysis,” Neurology 2004; 63: 1230-1233 (October).