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.