Recent reports have suggested an association between the use of oral bisphosphonates and oesophageal cancer. However, a ten-year cohort study using data from the UK General Practice Research Database (GPRD) found that the use of oral bisphosphonates was not significantly associated with incident oesophageal or gastric cancer.

The study compared the incidence of oesophageal and gastric cancer in a cohort of patients treated with oral bisphosphonates between January 1996 and December 2006 with incidence in a control cohort. Cancers were identified from relevant Read/Oxford Medical Information System codes in the patient's clinical files. The main outcome measure was hazard ratio for risk of oesophageal and gastric cancer in bisphosphonate users compared with nonusers, with adjustment for potential confounders (smoking, alcohol consumption, body mass index and drug therapy - hormone therapy, nonsteroidal anti-inflammatory drugs, H2 receptor antagonists, and proton pump inhibitors).

The following results were reported:

• The mean 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 cohort (81% women; mean age, 70.0 (SD, 11.4) years).
• One hundred sixteen oesophageal or gastric cancers (79 oesophageal) occurred in the bisphosphonate cohort and 115 (72 oesophageal) in the control cohort.
• The incidence of oesophageal and gastric cancer combined was 0.7 per 1000 person-years of risk in both the bisphosphonate and control cohorts; the incidence of oesophageal cancer alone in the bisphosphonate and control cohorts was 0.48 and 0.44 per 1000 person-years of risk, respectively.
• There was no difference in risk of oesophageal and gastric cancer combined between the cohorts for any bisphosphonate use (adjusted hazard ratio, 0.96 [95% confidence interval, 0.74-1.25]) or risk of oesophageal cancer only (adjusted hazard ratio, 1.07 [95% confidence interval, 0.77-1.49]).
• There was also no difference in risk of oesophageal or gastric cancer by duration of bisphosphonate intake.

The authors concluded that in the UK GPRD patient population no evidence was found for a substantially increased risk of oesophageal (or gastric) cancer in persons using oral bisphosphonates. They noted that these drugs should not be withheld, on the basis of possible oesophageal cancer risk, from patients with a genuine clinical indication for their use.