Calcitonin nasal spray and increased cancer risk: a population-based nested case-control study.

Context: The concern regarding cancer risk has resulted in the recommendation to pull calcitonin nasal spray (CNS) from the market.
Objective: We conducted a nested case-control study to evaluate the association between CNS use in osteoporosis patients in Taiwan and their subsequent risk of cancer.
Design: This was a population-based nested case-control study.
Setting: Data were obtained from the Taiwan National Health Insurance Research Database.
Patients or Other Participants: The study cohort consisted of 28 222 patients diagnosed with osteoporosis between January 1, 2000, and December 31, 2011. We identified 1925 cancer patients as the study group and 2 noncancer patients frequency matched according to age at index date, sex, comorbidity, index-year, and osteoporosis-year as the control group.
Main Outcome Measures: Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression analysis.
Results: Use of CNS in women with osteoporosis significantly increased the risk of liver cancer (OR = 1.94, 95% CI = 1.23-3.05) but decreased the risk of breast cancer (OR = 0.35, 95% CI = 0.15-0.80). Further analysis of monthly CNS dosages showed that the association between CNS and liver cancer is limited to higher-dose users.
Conclusion: The findings of this population-based nested case-control study suggest that CNS use might increase the risk of liver cancer in female osteoporosis patients but decrease the risk of breast cancer. Our data do not completely support the decision to discontinue use of CNS in osteoporosis patients.