More colon cancer with more frequent antibiotics
Colon cancer is one of the three most common types of cancer in Germany
Quelle: Getty Images/Science Photo Libra
A new study shows that people who take antibiotics frequently and for long periods of time are slightly more likely to develop colon cancer. Surprisingly: In some cases, the bacteria killers seem to protect against the tumors.
Antibiotics are a blessing in medicine and save lives every day. However, they also have downsides, as the active ingredients can potentially kill beneficial bacteria as well. Frequent use of antibiotics can therefore slightly increase the risk of colon cancer, according to a team led by Sophia Harlid from Umeå University in Sweden. The extensive study was published in the “Journal of the National Cancer Institute”. Frequent antibiotic use increased the likelihood of developing colon cancer by 17 percent.
Colon cancer is one of the three most common types of cancer in Germany: the disease is newly diagnosed in around 60,000 people nationwide. Colon cancer is by far the most common form.
The Swedish researchers explain their result by saying that antibiotics in the intestine change the microbiome – i.e. the community of microorganisms. A healthy intestinal lining is colonized by many different strains of bacteria.
The intestines are colonized by many beneficial bacteria.
Quelle: Getty Images/Science Photo Libra
This so-called intestinal flora plays an important role for the immune system. Antibiotics can damage the intestinal flora. This can lead to diarrhea or inflammation – and, as the study shows, also increase the risk of colon cancer.
The German expert Andreas Stallmach from the Jena University Hospital emphasizes that antibiotics should be used responsibly. “There are people who have a kind of scar in the microbiome after taking antibiotics,” explains Stallmach, who was not involved in the study. Why this happens to some people and not to others is the subject of current research, says the director of the Clinic for Gastroenterology.
Stallmach was impressed with the size of the study. In it, the researchers compared over 40,000 colorectal cancer patients with more than 200,000 people without the disease. The information, which comes from large databases, also indicates who had taken antibiotics between 2005 and 2016.
Long-term antibiotics are particularly dangerous
Antibiotic therapy for more than six months in particular increased the risk of developing a tumor in the upper sections of the colon. Most of the bacteria that are killed by antibiotics live there. But not every antibiotic seems to have the same effect: according to the analysis, classes of active substances such as quinolones increase the risk particularly strongly.
In the rectum, the last part of the large intestine, the opposite effect was found: there, women who had taken antibiotics were less likely to develop tumors. One possible explanation: infections with chlamydia, for example, often cause inflammation of the intestinal mucosa in women. This can also contribute to the development of cancer. Successful antibiotic therapy eliminates the pathogen so that the mucous membrane can recover, the researchers suspect.
“Our results underline the fact that there are many reasons not to prescribe antibiotics generously,” explains Harlid in a statement from her university. Many diseases would heal without antibacterial therapy.
Stallmach also advocates a rational use of antibiotics. Nevertheless, the drugs are still indispensable for treating bacterial infections. Does anyone who has taken antibiotics have to worry about colon cancer? “There is absolutely no need to worry just because you took antibiotics,” says Harlid.
“Patients who take antibiotics for a longer period of time should definitely take part in colorectal cancer screening,” advises Stallmach. With a regular colonoscopy, tumors can be discovered and removed at an early stage. In Germany, colorectal cancer screening is covered by statutory health insurances for men from the age of 50 and for women, due to a generally lower risk, from the age of 55.
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