Bisphosphonates and esophageal cancer: A RADAR report.

Abstract

4063 Background: In 2009, the US Food and Drug Administration (FDA) reported on 23 patients who had developed distal esophageal cancer, with alendronate (ALN) within 2 years of initiation of therapy. Similarly, 31 cases of esophageal cancer were reported from Europe and Japan. Esophagitis has been associated with oral BPs. Erosive esophagitis and persistent mucosal abnormalities have been noted with crystalline material (similar to ground ALN). Our objective was to assess the FDA Adverse event reporting system (FDA AERS) for a safety signal. Methods: The FDA Adverse Event Reporting System (AERS) database was searched using terms related to esophageal cancer combined with all drug names for bisphosphonates (search period:1996-2010). Disproportionality ratios were calculated: Proportional reporting ratio (PRR) and Empiric Bayes Geometric Mean (EBGM) determining that the esophageal cancer cases were more common with bisphosphonates than with other drugs in the database. Results: We identified 128 cases of bisphosphonate-associated esophageal cancer; 114 (89%) female and 14 male (11%), mean age 72 ± 12 yrs; the drugs included alendronate (n=96, 75%), risedronate sodium (n=14, 11%), ibandronic acid (n=10, 7.8%), zoledronic acid (n=7, 5.4%) and pamidronate (n=1, 1%). Barrett’s esophagus was listed in 3 cases of esophageal carcinoma. A significant safety signal was found only for alendronate with a PRR= 6.4 (95% C.I. 5.29, 7.730; p=0.001), EBGM = 6.3 (95% C.I. 5.1, 7.6 p=0.001). Conclusions: Our analysis of FDA AERS identifies a larger number of cases of esophageal cancer than previously described, and a significant safety signal with alendronate use. Avoidance of oral bisphosphonates in patients with Barrett’s esophagus, and persistent mucosal abnormalities is recommended. Increased awareness and vigilance is needed for patients receiving oral bisphosphonate therapy.