Meta-analysis: oral bisphosphonates and the risk of oesophageal cancer

Background Bisphoshonates, which are used in the treatment and prevention of osteoporosis, have recently been implicated in the development of oesophageal cancer; however, studies report conflicting data. Aim To conduct a meta-analysis of studies reporting on the association between bisphosphonates and oesophageal cancer to quantify the relationship. Methods A search was conducted through Medline, PubMed, Embase and Current Contents Connect to 2 August 2012. We calculated pooled odds ratios and 95% CIs using a random effects model for the risk of oesophageal cancer associated with exposure to bisphosphonates, as well as for the different periods of exposure. Results Seven studies, with 19 similar to 700 oesophageal cancer cases, met our inclusion criteria. We found a positive relationship between exposure to bisphosphonates and oesophageal cancer, with an odds ratio (OR) of 1.74 with a 95% CI of 1.192.55. Heterogeneity was observed (I2 similar to=similar to 85%, P similar to<similar to 0.001). Publication bias was not present. An increased risk of oesophageal cancer was also found in the group exposed to bisphosphonates for a longer period of time, compared with the group who experienced a shorter period of exposure (OR 2.32; 95% CI 1.573.43 vs. OR 1.35; 95% CI 0.772.39). An increased risk was associated with exposure to Etidronate (OR 1.58; 95% CI 1.122.24), but not to Aledronate. Conclusions Exposure to bisphosphonates may be associated with an increased risk of oesophageal cancer. More studies are needed to confirm the relationship.