Family cancer history strongly predicts colorectal cancer risk in IBD patients

A new Swedish study finds that people with inflammatory bowel disease who have multiple close relatives with colorectal cancer face a significantly higher risk of developing the disease themselves, potentially challenging current screening guidelines. The registry study from Karolinska Institutet, published in Gastroenterology, tracked 124,387 IBD patients against 1.2 million controls for a median of 11 years. Those with two or more affected first-degree relatives were about 2.6 times more likely to develop colorectal cancer, compared to a less than 50% increased risk for those with one relative diagnosed before age 50. Current international guidelines focus on early-onset family cases, but researchers suggest the number of affected relatives may be a stronger risk marker. The study also found that IBD patients with affected relatives had similar absolute cancer risks to the general population with the same family history.