Cancer in Patients With Gabapentin (GPRD)

High doses of gabapentin are associated with pancreatic acinar cell tumors in rats, but there has been no post marketing pancreatic carcinogenicity signal with gabapentin as reported by spontaneous reports in AERS or in the published literature. In a published case-control screening study of the association of gabapentin with 55 cancers, the only cancer that met the screening criteria for possibly increased cancer risk with gabapentin exposure was renal (including renal pelvis) cancer. This association was judged to be likely due to or substantially accentuated by confounding by cigarette smoking, hypertension, and lifestyle (Cancer Causes Control 2009;20:1821-1835). The relationship between gabapentin exposure and pancreatic cancer and renal cancer is studied in NCT01138124, and supplemental analyses for these cancers are performed in the current study. The FDA recommended GSK also study the relationship between gabapentin and all-cancer sites, as well as cancer at the following specific sites: 1) stomach, 2) anus, anal canal, and anorectum, 3) lung and bronchus, 4) bones and joints, 5) breast, 6) penis, 7) urinary bladder, and 8) other nervous system. The primary objective of this study is to determine whether exposure to gabapentin is associated with an increased risk of developing all-cancer, and these specific cancers in the United Kingdom (UK) General Practice Research Database (GPRD). Each member of the UK population is registered with a General Practice, which centralizes the medical information not only from the general practitioners themselves but also from specialist referrals and hospital attendances. Over 487 General Practices contribute data to the GPRD. The study cohort from which cases and controls are drawn is all subjects in the GPRD 1993-2008. Gabapentin was approved in the UK in May 1993. Entry into the study cohort begins Jan 1, 1993 for all those who are registered in GPRD before that time, and at the time of registration if later than Jan 1