Exposure to bisphosphonates and risk of common non-gastrointestinal cancers: series of nested case–control studies using two primary-care databases

BACKGROUND: Bisphosphonates are the most commonly prescribed osteoporosis drugs but long-term effects are unclear, although antitumour properties are known from preclinical studies. METHODS: Nested case–control studies were conducted to investigate bisphosphonate use and risks of common non-gastrointestinal cancers (breast, prostate, lung, bladder, melanoma, ovarian, pancreas, uterus and cervical). Patients 50 years and older, diagnosed with primary cancers between 1997 and 2011, were matched to five controls using the UK practice-based QResearch and Clinical Practice Research Datalink (CPRD) databases. The databases were analysed separately and the results combined. RESULTS: A total of 91 556 and 88 845 cases were identified from QResearch and CPRD, respectively. Bisphosphonate use was associated with reduced risks of breast (odds ratio (OR): 0.92, 95% confidence interval (CI): 0.87–0.97), prostate (OR: 0.87, 95% CI: 0.79–0.96) and pancreatic (OR: 0.79, 95% CI: 0.68–0.93) cancers in the combined analyses, but no significant trends with duration. For alendronate, reduced risk associations were found for prostate cancer in the QResearch (OR: 0.81, 95% CI: 0.70–0.93) and combined (OR: 0.84, 95% CI: 0.75–0.93) analyses (trend with duration P-values 0.009 and 0.001). There were no significant associations from any of the other analyses. CONCLUSION: In this series of large population-based case–control studies, bisphosphonate use was not associated with increased risks for any common non-gastrointestinal cancers.