Study reveals no evidence of link between bisphosphonates to esophageal cancer risk

Although some reports have suggested a link between the use of oral bisphosphonates (drugs that prevent the loss of bone mass) and esophageal cancer, analysis of medical data from more than 80,000 patients in the United Kingdom found that use of these drugs was not significantly associated with new cases of esophageal or gastric cancer, according to a study in the August 11 issue of JAMA.

Bisphosphonates are mainly used to prevent or treat osteoporosis, especially in postmenopausal women. Their use has increased dramatically in recent years in the United States and other Western populations, and are now commonly prescribed in elderly women, according to background information in the article. "Esophagitis [inflammation of the esophagus] is a known adverse effect of bisphosphonate use, and recent reports suggest a link between bisphosphonate use and esophageal cancer, but this has not been robustly investigated," the authors write. "Large studies with appropriate comparison groups, adequate follow-up, robust characterization of bisphosphonate exposure, and information on relevant confounders are required to determine whether bisphosphonates increase esophageal cancer risk."

Chris R. Cardwell, Ph.D., of Queen's University Belfast, United Kingdom, and colleagues investigated the association between bisphosphonate use and esophageal cancer by extracting data from the UK General Practice Research Database of patients treated with oral bisphosphonates, along with a group of patients not treated with these drugs (control cohort), between January 1996 and December 2006. Average follow-up time was 4.5 and 4.4 years in the bisphosphonate and control cohorts, respectively.

Excluding patients with less than 6 months follow-up, there were 41,826 members in each group (81 percent women; average age, 70.0 years). One hundred sixteen esophageal or gastric cancers (79 esophageal) occurred in the bisphosphonate cohort and 115 (72 esophageal) in the control cohort. Analysis of the incidence of these cancers among the bisphosphonate and control groups found no difference in risk of esophageal and gastric cancer combined between the cohorts for any bisphosphonate use or risk of esophageal cancer only. There also was no difference in risk of esophageal or gastric cancer by duration of bisphosphonate intake.

"In conclusion, in the UK GPRD patient population we found no evidence for a substantially increased risk of esophageal (or gastric) cancer in persons using oral bisphosphonates. These drugs should not be withheld, on the basis of possible esophageal cancer risk, from patients with a genuine clinical indication for their use," the authors write.