Hyunseok Kang, MD, MPH, from Johns Hopkins University in Baltimore, and colleagues analyzed linked data from the National Veterans Affairs (VA) medical SAS data set (2002–2008) and the VA Central Cancer Registry. Cancer incidence was assessed in a cohort of 26,911 veterans >40 years who were followed in the VA system for at least one year for one of four diagnoses: bipolar disorder, posttraumatic stress disorder, migraines, and seizures. A group of 412,717 non-VPA users was also followed.
The researchers observed a significant reduction in the risk of cancers of the head and neck associated with VPA use (hazard ratio [HR], 0.66). Associations were observed for treatment duration and median VPA drug levels. There were no significant differences in the incidence of cancers of the lung (HR, 1.00; 95% confidence interval [CI], 0.84–1.19), bladder (HR, 0.86; 95% CI, 0.64–1.15), colon (HR, 0.95; 95% CI, 0.74–1.22), or prostate (HR, 0.96; 95% CI, 0.88–1.12).
“Use of VPA is associated with a lower risk of developing head and neck cancers,” the authors write.
One author disclosed financial ties to the pharmaceutical industry.