Commentary on “Benzodiazepine use possibly increases cancer risk: A population-based retrospective cohort study in Taiwan.” Kao CH, Sun LM, Su KP, Chang SN, Sung FC, Muo CH, Liang JA, Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan.: J Clin Psychiatry 2012;73(4):e555–e60

Abstract

To evaluate the possible association between benzodiazepine use and subsequent cancer risk in Taiwan. In this population-based retrospective cohort study, we used data from 1996 to 2000 obtained from the Taiwanese National Health Insurance system to investigate the possible association between benzodiazepine use and cancer risk. The exposure cohort (mean age = 47.9 years, standard deviation = 17.3 years) consisted of 59,647 patients using benzodiazepine. Each patient from the exposure cohort was randomly frequency matched by age and sex to a person from the cohort with no benzodiazepine exposure (the comparison group; mean age = 46.4 years, standard deviation = 17.8 years). Each study subject was followed until a diagnosis of cancer was made (according to the International Classification of Diseases Ninth Revision Clinical Modification) or until the time the subject was censored for loss to follow-up, death, or termination of insurance, or to the end of 2009. A Cox proportional hazard regression analysis was conducted to estimate the effects of benzodiazepine use on cancer risk. In the group with benzodiazepine use, the overall risk of developing cancer was 19% higher than in the group without benzodiazepine exposure, and the difference between the groups was statistically significant (hazard ratio [HR] = 1.19; 99.6% confidence interval [CI], 1.08-1.32). With regard to individual types of cancer, the risks of developing liver cancer (HR = 1.45; 99.6% CI, 1.10-1.90), prostate cancer (HR = 1.72; 99.6% CI, 1.10-2.70), and bladder and kidney cancer (HR = 1.76; 99.6% CI, 1.16-2.67) were significantly higher for the benzodiazepine cohort. This population-based study has shed light on a possible relationship between benzodiazepine use and increased cancer risk. Further large, thorough investigations are needed to confirm these findings.