Compared with elderly patients, the use of antibiotics may make young patients more prone to colon cancer. The use of antibiotics seems to be associated with the incidence of colon cancer, especially in young people, and may lead to an increase in the number of cases of early-onset colorectal cancer (CRC), British researchers said. Previous studies have shown that significant changes in the structure and diversity of intestinal microbiome caused by antibiotic treatment can affect the incidence of colorectal cancer in the elderly, but no study has analyzed the impact of antibiotic use on early-onset colorectal cancer.
Therefore, the researchers conducted a nested case-control study of primary care records to identify cases of colorectal cancer diagnosed in Scotland between 1999 and 2011. Patients were divided into patients diagnosed before the age of 50 and patients diagnosed at the age of 50 and over. The study included 7903 cases of CRC, including 5281 cases of colon cancer, 2622 cases of rectal cancer, and 30418 control individuals. Among CRC patients, 445 (5.6%) were under 50 years old at the time of diagnosis.
The research team also analyzed the antibiotic use history, extracted the prescription of oral antibiotics, stratified by drug category and anaerobic / non anaerobic effect, and calculated the total antibiotic use period, which was divided into 0 days, 1-15 days, 16-60 days and > 60 days.
Among young patients, patients with antibiotic use period of 1-15 days had the greatest association between antibiotic use and colon cancer (adjusted odds ratio, 1.55), patients with antibiotic use period of 16-60 days decreased to 1.46, while patients with antibiotic use period > 60 days showed no association. This relationship was not found in colon cancer patients aged 50 years and over at the time of diagnosis.
There was no significant relationship between the use of antibiotics and the incidence of rectal cancer. The adjusted odds ratio was 1.17 for patients under 50 years old and 1.07 for elderly patients.
Specifically, the use of antibiotics resulted in an adjusted odds ratio of 1.49 for colon cancer in patients under 50 years old and 1.09 for patients over 50 years old. Overall, 45% of patients took antibiotics. The use of any antibiotic is associated with a significantly increased risk of colon cancer, but this is most evident in patients younger than 50 years at the time of diagnosis.
The results showed that people under the age of 50 with a history of antibiotic use had a 49% increased risk of colon cancer (but not rectal cancer).
“To our knowledge, this is the first study to link antibiotic use with an increased risk of early-onset colon cancer,” said Sarah Perrott, a medical student at the University of Aberdeen in Scotland. Colon cancer has increased at least 3% a year over the past 20 years. ”
“Junk food, sugary drinks, obesity and alcohol may be responsible for this growth, but our data emphasize the importance of avoiding unnecessary antibiotics, especially in children and young people.”
Leslie Samuel, the study’s lead author and oncologist at Aberdeen Royal infrared, added: “we now want to find out whether there is a link between the use of antibiotics and changes in the microbiome, and whether it will make people more vulnerable to colon cancer, especially young people.”“ This situation is complicated because we know that even if the intestine has been cleaned for diagnosis, the microbiome can quickly return to its previous state. ”
The study was published at the World Congress on gastroenteric cancer of the European Society of Oncology (ESMO) in 2021 on July 2.
Alberto sobrero, an oncologist at Ospedale San Martino hospital in Genoa, Italy, commented: “the prognosis of young patients with colon cancer is usually worse than that of the elderly because they are usually diagnosed late. Compared with patients in their 70s, if a patient in his 30s feels abdominal discomfort, doctors are less likely to examine him for colon cancer because young patients do not meet the conditions for cancer screening. ”
However, sobrero believes that it is too early to say that overuse of antibiotics may be a pathogenic factor. Before considering the impact of antibiotics on intestinal flora, we need to know more about the role of microbiome in colorectal cancer. Nevertheless, the findings “remind us that antibiotics should not be used unless they are really needed,” he concluded. We cannot rule out the possibility that unnecessary use of antibiotics may increase people’s risk of cancer. ”
Thomas seufferlein, MD, Department of internal medicine, ULM University, Germany, agrees with the author that “it is wise and important to use antibiotics carefully”. But he also said that more research is needed on the relationship between the use of antibiotics and the increase of early colorectal cancer.