KUALA LUMPUR, August 22 — A new study has lead researchers to conclde that taking even a single short term course of antibiotics might increase the risk of developing colon cancer a decade later.
This finding further highlights the need for strengthening of cautious use of antibiotics, which are frequently improperly or over-prescribed.
The study which involved an extensive data mining analysis of British medical records, looked at 28,890 cases of colorectal cancer over a 23 year period from 1 January 1989, to 31 December 2012.
The medical records of 19,276 patients diagnosed with bowel cancer and 9,254 patients with rectal cancers were followed for at least two years. Researchers also looked at 137,077 patients who didn’t develop these cancers.
The findings, which were published in the August 20 issue of the journal Gut, showed that after taking account of potential risk factors, such as having a history of obesity, smoking, alcohol use, and diabetes, those who developed colon cancer were slightly more likely to have been exposed to antibiotics for a period of 16 days or more.
However, those with rectal cancers did not show that association despite having the same antibiotic exposure compared to healthy subjects. This implied that while risk of colon cancer increased, there was no apparent increase in risk for rectal cancer.
The researchers found that the type of antibiotic prescribed also appeared to affect the risk of cancer and its location.
Those prescribed with penicillins were consistently associated with an increased risk of bowel cancer of the proximal colon. Ampicillin/amoxicillin was the penicillin most commonly prescribed in those reviewed. On the other hand, prescriptions of tetracyclines were assosciated a lower risk of rectal cancer.
The study was carried out by the University of East Anglia Norwich Medical School, Norfolk and Norwich University Hospital NHS Trust, UK and Johns Hopkins University School of Medicine, USA.
It investigated the long-lasting impact of antibiotics on the gut microbiome, which is the balance of helpful and harmful bacteria in the gut, and the risk to bowel and rectal cancer.
The researchers note that because this was an observational study, the findings do not show cause and effect.
In 2010, globally patients took an estimated 70 billion doses of antibiotics – equivalent to 10 doses each.
