Looking at data from the Saskatchewan Cancer Agency registry, researchers isolated 3,367 people who were diagnosed with colorectal between the years of 1991 and 2000. After comparing this group with over 13,000 people of similar age and lifestyles who were not diagnosed with colorectal cancer, the researchers found that those who had used SSRIs daily up to five years earlier had a significantly lower risk of colorectal cancer. The results were published in The Lancet Oncology.
Dr. Wanning Xu of McGill University in Montreal and colleagues theorize that SSRIs may reduce the risk of colorectal cancer by inhibiting the growth of tumor cells.
However, other experts suggest that it is too difficult to draw any conclusions from this study. "An observational study, such as that by Xu and colleagues, can be difficult to interpret," writes Dr. Henrik Sorensen from Aarhus University, Denmark, in a commentary accompanying the study.
Because the study examined a pre-existing group of people in a registry, there are many factors that may have skewed the results of the study. In fact, the authors note that many risk factors for colorectal cancer, such as smoking, obesity and lack of exercise, are also risk factors for depression.
Both Xu and Sorensen recommend further studies to clarify the role that SSRIs may play in preventing colorectal cancer.
Until then, writes Sorensen, clinicians should not consider prescribing SSRIs only to prevent colorectal cancer.
