Colorectal cancer complicating Crohn's disease

Some earlier studies have indicated that patients with inflammatory bowel d isease, especially those with long-standing and extensive ulcerative coliti s, have an increased risk of colorectal cancer. Moreover, others in tertiar y care centres have suggested that patients with Crohn's disease also have a higher risk of colorectal cancer. Canadian data on colorectal cancer in C rohn's disease appear to be limited. For this investigation, a single clini cian database of 877 patients with Crohn's disease was used. Altogether, th ere were six patients with colorectal cancer (ie, overall rate of 0.7%). Al l of these patients were men with an initial diagnosis of Crohn's disease e stablished at a mean age of approximately 28 years, with either ileocolonic disease or colonic disease alone, but not with ileal disease alone. Althou gh there was a predominance of women in the overall study population (ie, 5 6.1%), no women developed colorectal cancer. The clinical behaviour of Croh n's disease was classified as nonstricturing in all six patients with color ectal cancer, but in two patients, Crohn's disease was complicated by a per irectal abscess or a fistula. All cancers were located in the rectum and we re diagnosed 30 years, 22 years, seven years, 18 years, 20 years and 40 yea rs after Crohn's disease was initially diagnosed. In three patients, the ca ncer was detected in a residual rectal stump after a partial colon resectio n at least 10 years earlier. In five patients, localized extension of disea se through the serosa, nodal or distant metastases (ie, liver, lung) was fo und at the time of cancer diagnosis; two patients have since died. The pres ent study confirms that Crohn's disease involving the colon may be a possib le risk factor for the development of colorectal cancer, at least in younge r men, but, in this study, not in women. However, part of this increased ri sk in men may have been related to the presence of a rectal stump, rather t han to Crohn's disease per se.