A new study, conducted by 9 authors from US and UK and published online, has found that oral antibiotic use has a link with higher risks of bowel cancers.
If you are a doctor who prescribes antibiotics, this study may mean you need be more judicious in your antibiotic prescribing pattern.
Similarly, if you an individual living in countries where antibiotics are not regulated and indulge in self-medication, you may just be doing yourself more harm than good.
Oral antibiotics – pills/capsules prescribed to kill bacteria and prevent them from multiplying – are widely used medicines worldwide.
For example, a WHO report noted a wide difference in antibiotic use for countries that had data to participate in the antibiotic use collation.
“The report finds wide discrepancies in consumption rates between countries, ranging from approximately 4 defined daily doses (DDD)/1000 inhabitants per day to more than 64 DDD.”
WHO is currently advocating for rational use of antibiotics to limit antibiotic resistance which according to CDC is defined as follows:
“Antibiotic resistance occurs when bacteria develop the ability to defeat the drugs designed to kill them.
When bacteria become resistant, antibiotics cannot fight them, and the bacteria multiply.”
But this new study is adding another dimension to the need to use antibiotics with caution.
The study published in the journal Gut of the British Medical Journal found that individuals who used oral antibiotics had a heightened risk of colon cancers but less of rectal cancers.
Antibiotics with anti-anaerobic bacteria – those not needing oxygen – have a higher association with increased colon cancers than those that are not.
Penicillins, especially ampicillin/amoxycylin, have higher association with colon cancer than others, while tetracyclines reduce the risks of rectal cancers.
Also, the antibiotic-cancer association was dose dependent, meaning the more the quantity of antibiotics consumed, the more the association.
Likewise, the association was found for antibiotic use of greater than 10 years before the diagnosis of the cancers.
The study was carried out using Clinical Practice Research Datalink (CRPD) from 1989 to 2012 from the UK and one of the largest collection of patients’ data.
The authors noted:
“The CPRD is one of the world’s largest electronic medical record databases of anonymised clinical records with population-based data collected prospectively.
At the time of this study, CPRD incorporated longitudinal medical records of 11.3 million patients from 674 practices in the UK, representing 6.9% of the UK population.”Excerpts from the report of the study published in BMJ.
The authors concluded that the findings from the study might have occurred because of the effects of the antibiotics on the gut microbiota.
“This effect heterogeneity may suggest differences in gut microbiota and carcinogenesis mechanisms along the lower intestinal tract.”Conclusion drawn by the authors from the study as quoted from abstract of the published article.
For further information: Jiajia Zhang et al, Oral antibiotic use and risk of colorectal cancer in the United Kingdom, 1989–2012: a matched case–control study, Gut (2019). DOI: 10.1136/gutjnl-2019-318593