Researchers at the University of Oxford's Cancer Epidemiology Unit and the Medicines and Healthcare Products Regulatory Agency studied 2,954 cases of men and women age 40 and older diagnosed from 1995 to 2005 with esophageal cancer, 2,018 with stomach cancer and 10,641 with colorectal cancer. Each case was compared with five controls matched for age, sex and habits.
Dr. Jane Green, the lead author, analyzed data from the U.K. General Practice Research Database's 6 million anonymous patient records.
"Esophageal cancer is uncommon. The increased risks we found were in people who used oral bisphosphonates for about five years, and even if our results are confirmed, few people taking bisphosphonates are likely to develop esophageal cancer as a result of taking these drugs," Green said in a statement.
"Our findings are part of a wider picture. Bisphosphonates are being increasingly prescribed to prevent fractures, and what is lacking is reliable information on the benefits and risks of their use in the long-term."
The findings are published in the British Medical Journal.