Antibiotic Use May Increase Colorectal Cancer Risk

More frequent antibiotic use increases the risk of colorectal cancer (CRC), according to the results of a new study.

To better understand the impact of antibiotic use on gut microbiota, the researchers conducted a nationwide, population-based study in Sweden. Included were 40,545 cases of CRC and 202,720 control cases from Sweden’s national registers between 2005 to 2016.

The results indicated a positive association between the risk of CRC and more-frequent antibiotic use. Antibiotics prescribed within 2 years of diagnosis reduced this association and were excluded from the study results. 

Further, this positive association was specific to the proximal colon (adjusted odds ratio for very high use vs no use, 1.17; 95% CI, 1.05-1.31). Proximal colon cancer was also positively associated with the use of quinolones and sulfonamides and/or trimethoprim. The risk of rectal cancer had an inverse relationship with more-frequent antibiotic use across antibiotic classes. This relationship was only observed in women. CRC risk was not associated with the use of methenamine hippurate.

“In conclusion, we observed a consistent association between antibiotics use and higher subsequent risk of proximal colon cancer and an inverse association for rectal cancer in women,” the researchers said. “Our findings strengthen prior evidence and provide new insights into site-specific carcinogenesis as well as indirect support for the role of gut microbiota.”

—Leigh Precopio

Reference:

Moon Lu SS, Mohammed Z, Häggström C, et al. Antibiotics use and subsequent risk of colorectal cancer: a Swedish nationwide population-based study. J Natl Cancer Inst. Published online September 1, 2021. https://academic.oup.com/jnci/advance-article/doi/10.1093/jnci/djab125/6360113