Mood Stabilizer Linked to Lower Risk of Cancer

Use of the common mood stabilizer and antiseizure medication valproic acid (VPA) was associated with an approximate one-third reduction of head and neck cancer in a recent retrospective cohort study.

“This is the first study to establish a potential benefit of VPA on cancer prevention, and the first study to examine the effects of VPA on head and neck cancer risk,” said senior author Dr. Johann Brandes, assistant professor of hematology and medical oncology of the Emory University School of Medicine and Winship Cancer Institute at Emory University in Atlanta, Georgia.

As Dr. Brandes explained, head and neck cancer affects approximately 50,000 patients in the United States each year, and the risk reduction that researchers observed in this study with VPA use could potentially result in the prevention of up to approximately 16,000 new cases and 3,000 to 4,000 annual deaths in this country alone.  

Because VPA inhibits histone deacetylases, the authors investigated the effects of the medication on the risk of developing lung, head and neck, prostate, bladder, and colon cancers.  

Dr. Brandes and colleagues analyzed data involving 439,628 veterans over the age of 40 years; 26,911 participants were taking VPA for bipolar disorder, posttraumatic stress disorder, migraines, and seizures.

The use of VPA for at least 1 year was linked to a 34% reduction in the risk of head and neck cancer. Researchers also found that higher doses and longer durations of treatment with VPA seemed to be related to even greater reductions.

Further, there were no significant differences detected in cancer incidence for lung, bladder, colon, and prostate cancers.

“Observations in the laboratory led us to hypothesize that VPA could prevent all forms of smoking-related cancers, such as lung, head and neck, and bladder cancer,” said Dr. Brandes. “The fact that we did not find an association between VPA use and lung and bladder cancer risk was unexpected.”

According to Dr. Brandes, a limitation of the study is its retrospective nature, which proves an association but not cause and effect.

“Even with the results of this study, there are insufficient data to recommend routine use of VPA for head and neck cancer chemoprevention,” he cautioned when asked about the practical implications of the study findings. “Since, as our data show, the benefit of VPA was limited to patients with therapeutic drug levels, periodic monitoring of these should be considered.”

In terms of future research, Dr. Brandes said that they are “working in the laboratory to identify biomarkers that may predict which patients may particularly benefit from VPA use and will consider testing these subsequently in a clinical study.”

This study was published in Cancer.

-Meredith Edwards White

Reference:

1. Kang H, Gillespie TW, Goodman M, et al. Long-term use of valproic acid in US veterans is associated with a reduced risk of smoking-related cases of head and neck cancer. Cancer. 2014 Mar 24. [Epub ahead of print]