… but patients should not be alarmed, says a Danish professor.
According to new Danish research published in Gastroenterology, people who have inflammatory bowel disease (IBD) such as ulcerative colitis or Crohn’s disease in childhood have an increased risk of developing cancer later in life.
The new research indicates that an early diagnosis of IBD doubles the risk of developing cancer, but the absolute numbers are still so small that people with IBD should not worry.
“We need to use this result to give both patients and their healthcare professionals proper information on the increased risk of developing cancer if they had IBD in childhood. There is an increased risk, but it is still so small that patients should merely focus on and get help with keeping their IBD under control and not otherwise worry,” explains Tine Jess, Center Director, Professor, MD, DMSc, Department of Epidemiology Research, Statens Serum Institut, Copenhagen.
50,000 Danes have IBD
The research is inspired by a similar study in Sweden that showed a two-fold risk of developing cancer if people had IBD in childhood.
Ulcerative colitis is characterized by chronic and bleeding inflammation of the colon, while Crohn’s disease is also present in the small intestine. Neither disease can be cured, and when surgeons remove parts of the inflamed intestine, the diseases move elsewhere in the intestines.
50,000 Danes have one of these two types of IBD, which result in blood in the stool, abdominal pain, diarrhoea and weight loss.
Researchers do not yet have a complete overview of the underlying causes of the development of IBD, but both genes and the environment seem to play a role.
5,300 participants with IBD
Tine Jess and colleagues examined the Danish National Patient Registry and the Danish Cancer Registry to link a diagnosis of IBD in childhood and the risk of developing cancer later in life.
Denmark has systematically collected patient data since 1977, and since then 5,300 children have been diagnosed with IBD.
The researchers had data from patients with an average follow-up time of 12 years, and 2.9% developed cancer during that period.
The researchers then compared this figure with a similar sample of 10 times as many people matched by sex and age in which 1.3% developed cancer.
“Like the study in Sweden, we found that IBD in childhood was associated with a two-fold increase in the risk of developing cancer. This can be a really difficult message for some patients who are already struggling with many problems related to their illness. But the figures show that the increase actually corresponds to only one extra case per year among 1,000 people. The key message is that the risk is incredibly small,” explains Tine Jess.
Men with IBD have a higher risk than women
The researchers also investigated whether people with IBD have an increased risk of developing specific types of cancer.
What the researchers discovered was that the risk is especially increased for skin cancer, lymphoma, liver cancer and gastrointestinal cancer.
In addition, the researchers found that men and women differed greatly in terms of increased risk.
Men were four times more likely to develop cancer if they had IBD as a child, whereas women only had a 50% increased risk.
Finally, the researchers found no difference in the increased risk between people with childhood diagnoses of ulcerative colitis versus Crohn’s disease.
The disease and not medicine increases the risk of cancer
In further studies, the researchers examined whether the risk could be associated with the underlying disease or the treatment received.
They found no difference between the different types of treatment. According to Tine Jess, this indicates that the higher risk of developing cancer is associated with the underlying disease and probably the chronic inflammation.
Many other studies have shown that increased inflammation increases the risk of developing many types of cancer.
“We know of cases in which treatment with strong immunosuppressive drugs can increase the risk of developing cancer, but this does not appear to apply to these people. The disease appears to be the reason,” says Tine Jess.
Focus on controlling IBD
Tine Jess says that the research findings can give patients with an early diagnosis of IBD certainty that, even though they have an increased risk of developing cancer, it is so small that they do not have to worry about it in their everyday lives.
Further, they should not worry that the medication they have chosen increases the risk of developing cancer more than other types of medication.
Nevertheless, the study also indicates that people with IBD should focus on taking their medication and trying to keep their IBD under control, because the inflammation is probably what increases the risk.
“They should focus on keeping the disease under control and should see their doctor regularly and be treated appropriately. This is the best way to reduce the risk of getting cancer if you have IBD,” says Tine Jess.
“Cancer risk in pediatric-onset inflammatory bowel disease: a population-based Danish cohort” has been published in Gastroenterology. In 2017, the Novo Nordisk Foundation awarded a grant to Tine Jess for the project Impact of Cardiometabolic Medications on Disease Course in Inflammatory Bowel Diseases: a Nationwide Danish Cohort Study.