Antidepressant use and colorectal cancer risk

A previous epidemiologic study reported a 30% reduced risk of colorectal cancer among users of high doses of selective serotonin reuptake inhibitors (SSRIs). We assessed the association of colorectal cancer risk with SSRI and tricyclic antidepressant use in our hospital-based Case Control Surveillance Study.

For the SSRI analyses, we used data collected on 529 colorectal cancer cases and 1955 hospitalized controls collected from 1995 to 2008. For the tricyclic antidepressant analyses, we used data on 2889 cases and 7122 controls collected from 1976 to 2008. We used multivariable logistic regression analysis to evaluate the association of regular SSRI use and regular tricyclic antidepressant use (daily use for at least 3 continuous months) with colorectal cancer risk.

The odds ratio for regular SSRI use was 0.55 (95% CI 0.35-0.88) and it did not differ by duration of use. The odds ratio was 0.47 (95% CI 0.26-0.85) for colon cancer and 0.72 (95% CI 0.37-1.41) for rectal cancer. The odds ratio for regular use of tricyclic antidepressants was 0.77 (95% CI 0.52-1.16)

We found an association of reduced risk of colorectal cancer with regular use of SSRIs. In light of laboratory data indicating that SSRIs may inhibit colon cancer and one previous epidemiologic study that also observed a decreased risk, further investigation of the effect of SSRIs on the risk of colorectal cancer is warranted.