Reduced antibiotic usage is emphasized as crucial in fighting bowel cancer, according to recent findings.

Antibiotic Use Linked to Early-Onset Colon Cancer, Study Finds

A new study presented at the ESMO World Congress on Gastrointestinal Cancer has linked antibiotic use to an increased risk of early-onset colon cancer. The study, titled "Global rise in early-onset colorectal cancer: an association with antibiotic consumption?" was conducted by a team led by Dr Leslie Samuel and supported by Cancer Research UK.

The research, which used a large Scottish primary care database of up to 2 million people, looked at nearly 8000 people with bowel cancer (colon and rectum) matched with people without bowel cancer. The study found that antibiotic use was associated with a significantly increased risk of proximal colon cancer (the first part of the colon) among individuals under 50 years.

Quinolones and sulfonamides/trimethoprim, which are used to treat a wide range of infections, were associated with these right-side cancers. In younger individuals, antibiotic use was linked to cancers in the first part of the colon. However, rectal cancer was not significantly associated with antibiotic usage in either age group, with the exception of non-anti-anaerobic antibiotics in the early-onset colon cancer cohort.

The study found that antibiotic use was associated with an increased risk of colon cancer across all ages, but the risk was increased by almost 50% in individuals under 50 years compared to 9% in those over 50 years. The authors of the study declare no conflicts of interest.

Dr Leslie Samuel, the senior author of the study, stated that the team now wants to find out if there is a link between antibiotic use and changes in the microbiome which can make the colon more susceptible to cancer, especially in younger people. Professor Alberto Sobrero, commenting on the new research, mentioned that younger people aged 20-40 with colon cancer generally have a worse prognosis than older people because they are often diagnosed later.

The contents of the right side of the colon may have a different microbiome compared to further along the colon. The study found limited evidence of a positive exposure-response relationship between antibiotic use and the risk of colon cancer, with the exception of proximal colon cancer in the early-onset colon cancer cohort. The funding for this work was provided by Cancer Research UK (reference C37316/A25535).

The authors of the study include Medhat A. Farag, Thomas Powles, and several others; the study was supported by funding from the Wellcome Trust and the Medical Research Council. The authors state that further research is needed to confirm the findings and to understand the mechanisms by which antibiotics may increase the risk of colon cancer.