The use of oral bisphosphonates was not found to be significantly associated with incident esophageal or gastric cancer, according to a retrospective analysis of patients from the UK General Practice Research Database. Based on their findings, Cardwell and colleagues concluded that, for patients in which they are clinically indicated, bisphosphonates should not be withheld solely on the basis of possible esophageal cancer risk.
Researchers analyzed data from 46,036 oral bisphosphonate users and 46,036 matched controls. With a mean follow-up of 4.5 years and 4.4 years for users and controls respectively, there were 181 esophageal cancers (92 in the control group) and 106 gastric cancers (57 in the control group). In both cohorts, 81% of patients were women, with a mean age of 70 years.
The analysis found no difference in the incidence of esophageal and gastric cancer combined or esophageal cancer alone. No increase in risk was associated with having been prescribed an oral bisphosphonate, a nitrogen-containing bisphosphonate, or non-nitrogen-containing bisphosphonate. In addition, no association was found between cancer risk and duration of bisphosphonate use or between cancer risk and a history of gastroesophageal reflux disease.
Study strengths include its size, duration of follow-up, and the use of recorded prescription data. Limitations, however, include the possibility of overestimation of bisphosphonate use due to the use of recorded prescription data, the potential for inaccurate incidence data due to the use of relevant diagnostic codes rather than cancer registry data, and the relatively high proportion of missing data on confounders.
The complete study will be published in the September issue of the Journal of the American Medical Association.