Risk for early-onset colorectal cancer (EOCRC) was not associated with recent antibiotic treatment, according to a study published in Clinical and Translational Gastroenterology.

Researchers sourced data for this population-based case-control study from the Swedish National Board of Health and Welfare database and the Epidemiology Strengthened by histoPathology Reports in Sweden (ESPRESSO) cohort. Patients (n=2557) aged younger than 50 years who were diagnosed with EOCRC between 2006 and 2016 were age- and gender-matched with up to 5 control participants (n=12,640). Risk for EOCRC was associated with antibiotic treatment in the 6 months prior to diagnosis. The primary outcome was EOCRC, and the secondary outcome was CRC at any age.

The case and control participants had a mean age of 42.9± 6.0 and 42.9±6.1 years; 46.2% and 46.3% were women; Charlson Comorbidity Index (CCI) was 0.2±0.9 and 0.1±0.5 points; and number of previous lower endoscopies was 0.2±1.3 and 0.02±0.17, respectively.

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Among the cases, 1416 had received treatment with antibiotics prior to their EOCRC diagnosis. Any antibiotic treatment was associated with increased risk for EOCRC (odds ratio [OR], 1.18; 95% CI, 1.07-1.29; P <.05). However, after adjusting for education, hospitalization, CCI, and previous endoscopies, antibiotic treatment was not associated with EOCRC risk (adjusted OR [aOR], 1.06; 95% CI, 0.96-1.17).

Stratified by spectrum of coverage, an association was observed between broad-spectrum antibiotics and EOCRC (aOR, 1.13; 95% CI, 1.02-1.26; P <.05). Further stratifying patients based on the number of previous antibiotic dispensation found that 2 dispensations of any antibiotics (aOR, 1.19; 95% CI, 1.03-1.37; P <.05) and 1 dispensation of a broad-spectrum antibiotic (aOR, 1.19; 95% CI, 1.05-1.35; P <.05) were associated with EOCRC. No associations were observed for bacterial target or anatomic therapeutic chemical.

Antibiotic treatment did not associate with EOCRC in any specific colorectal regions.

The study may have been limited by evaluating prescription dispensation and not actual use. In addition, Sweden has low antibiotic usage in general.

The study found no strong evidence that antibiotic exposure increased risk for EOCRC. These study findings contradict previous reports that found that antibiotic use increased risk for colorectal cancer among older individuals.

“These findings, as well as heterogeneous risk estimates based on antibiotic class and coverage, should be contextualized by our observation that even statistically significant differences were modest in magnitude and, thus, of unclear clinical importance,” the study authors noted. “Our results will need to be validated in other populations given Sweden’s lower antibiotic dispensation patterns compared with other nations, and although these results may be reassuring on some level, antibiotic stewardship and prescriber restraint should be practiced regardless, particularly for broad-spectrum antibiotics.”


Nguyen LH, Cao Y, Batyrbekova N, et al. Antibiotic Therapy and Risk of Early-Onset Colorectal Cancer: A National Case-Control Study. Clin Transl Gastroenterol. 2022;13(1):e00437. doi:10.14309/ctg.0000000000000437

This article originally appeared on Gastroenterology Advisor