Here’s another reason to avoid unnecessary use of antibiotics: Long-term use of antibiotics could increase your risk of developing colon cancer, researchers say.

“While in many cases antibiotic therapy is necessary and saves lives, in the event of less serious diseases which can be treated with other ways, doctors should be cautious in using antibiotic. Above all, we need to be cautious to prevent bacteria from developing antibiotic resistance. But our study shows that taking antibiotics may also increase the risk of developing colon cancer in the future”, said study author Sophia Harlid. She is a cancer researcher from Umeå University in Sweden.
However, there’s no reason to panic, she said.
“There is absolutely no cause for alarm if you have taken antibiotics. The increase in risk is moderate,” Harlid explained in a university news release.
This link to colon cancer might be due to the impact that antibiotics have on the intestinal microbiome (gut bacteria), according to the study.
The researchers analyzed data on 40,000 patients in the Swedish Colorectal Cancer Registry, and compared them with a control group of 200,000 cancer-free people in Sweden’s general population.
Investigators also examined antibiotic use data in Swedish Prescribed Drug Register.
They found that both women and men who took antibiotics for over 6 months had a 17% higher risk of developing cancer in the ascending colon than those who didn’t take antibiotics.
The increased risk of colon cancer became clearer 5 to 10 years after taking antibiotics. Even though those who took the most antibiotics had the greatest increase in risk, there was a small but statistically significant increase in the risk of colon cancer after a single course of antibiotics, according to the study.
There was no link between antibiotics and an increased risk of cancer in the descending colon or an increased risk of rectal cancer in men. Women taking antibiotics had a slightly reduced risk of rectal cancer, according to the researchers.
This study was published September 2021, in the Journal of the National Cancer Institute [1], and it confirms the results of an earlier smaller British study.
Source of information: Umeå University, news release, August 30, 2021
[1] Website link: https://academic.oup.com/jnci/advance-article/doi/10.1093/jnci/djab125/6360113?searchresult=1