The Carcinogenicity of Alendronate in Patients with Osteoporosis: Evidence from Cohort Studies

CONTEXT: Alendronate may relate to the incidence of cancers, especially esophageal and colon cancer. But the results are inconsistent in different studies. OBJECTIVE: To quantify the association between the use of alendronate and the occurrence of different types of cancer. DATA SOURCES: We searched Embase, Pubmed, CENTRAL, SIGLE and clinicaltrials.gov, up to 2014 June. STUDY SELECTION: Cohort studies reporting association between alendronate or bisphosphonate therapy including alendronate in patients with osteoporosis and risk of cancer were selected by two authors. DATA EXTRACTION: Two authors independently extracted the data. The Chi-square test and the I-square test were used for testing heterogeneity between studies. DATA SYNTHESIS: Eight cohort studies were included in the meta-analysis. Meta-analysis result manifested that alendronate significantly increased the incidence of lung cancer (HR 1.23, 95%CI 1.03 to 1.47, P value = 0.03), nevertheless, there was no significant difference after we excluded either Lee’s 2012 study (HR 1.17, 95%CI 0.95 to 1.44, P value = 0.13) or Chiang’s 2012 study (HR 1.47, 95%CI 1 to 2.17, P value = 0.05). For the incidence of colorectal cancer, no significant difference occurred (HR 0.91, 95%CI 0.74 to 1.13, P value = 0.39), but there was a positive relationship when we used fixed model (HR 0.85, 95%CI 0.78 to 0.93, P value = 0.004). For the incidence of liver cancer, there was no significant difference (HR 1.36, 95%CI 0.9 to 2.04, P value = 0.14), however, the result changed after we excluded Chiang’s 2012 study (HR 1.69, 95%CI 1.03 to 2.77, P value = 0.04). There was no significant difference in other types of cancer. CONCLUSION: Based on current evidences, alendronate therapy may be associated with a high risk of lung cancer, may with an excess risk of liver cancer, a low risk of colorectal and no related risk of other cancers.