To the Editor: The meta-analysis assessing the risk of venous thromboembolism (VTE) with bevacizumab in cancer patients by Dr Nalluri and colleagues1 carefully reviewed 15 well-conducted randomized controlled trials (RCTs) comparing bevacizumab therapy with placebo. However, because the authors failed to distinguish between incidence per treatment episode and incidence per unit of time (the more relevant statistic), their conclusions may be erroneous. In oncology clinical trials such as those reviewed, patients are generally not treated for a predetermined fixed period of time; rather, they are treated until their cancer shows evidence of progression on computed tomographic scans, at which time the patient is removed from the trial and further adverse events are not recorded beyond 30 days after the end of treatment.
Minor DR. Risk of Venous Thromboembolism With Bevacizumab in Cancer Patients. JAMA. 2009;301(14):1434-1436. doi:10.1001/jama.2009.439