Colorectal adenocarcinoma in Crohn's disease: a retrospective histologic study

The aim of this study was to review all histopathologic sections from surgical specimens with inflammatory bowel disease and colorectal carcinoma filed at this hospital between 1951 and 1996.

A total of 40 surgical (n = 39) or autopsy (n = 1) colon or colorectal specimens were reviewed. Internationally accepted histologic criteria were strictly applied to differentiate Crohn's disease (CD), ulcerative colitis (UC), and indeterminate colitis (IC).

Of the 40 specimens with inflammatory bowel disease and carcinoma, 22 (55 percent) had CD, 16 (40 percent) had UC, and the remaining 2 (5 percent) had IC. Males accounted for 72.7 percent or 16 of the 22 patients with colorectal carcinoma in CD and for 68.7 percent or 11 of the 16 patients with carcinoma in UC. Both patients with IC and carcinoma were males. The median age of patients at diagnosis was as follows: CD, 20 (range, 7-68) years; UC, 23 (range, 5-21) years. In IC, the age was 61 and 81 years, respectively. The median disease duration (before detection of colorectal cancer) was as follows: CD, 18.5 (range, 1-45) years; UC, 19 (range, 6-38) years. For cases with IC, it was 13 and 19 years, respectively. Median age of patients at cancer diagnosis was as follows: CD, 48 (range, 21-78) years; UC, 49 (range, 21-81) years. Ages at cancer diagnosis in IC were 68 and 81 years. Colorectal carcinoma tend to develop among relatively young patients with CD and UC. Mucinous adenocarcinomas accounted for approximately one-third of the carcinomas affecting CD. Thirty percent of old specimens (before the end of 1982) had in fact carcinoma complicating CD and not UC (the latter being the diagnosis appearing in old pathologic reports). During a time lapse of 38 years (i.e., between 1951 and 1989), only 11 cases of colorectal CD with carcinoma (i.e., 0.2 cases/year) were found, but as many as 11 during the past 6.5 years (i.e., 1.7 cases/year) have been diagnosed. Only 42.3 percent (11/26) of cases with colorectal inflammatory bowel disease and carcinoma operated on between 1951 and the end of 1989 had Crohn's colitis but as many as 78.6 percent (11/14) of those operated on between 1990 and May 1996 had Crohn's colitis. Review of the literature indicated that 64.8 percent or 191 of the 295 cases of colorectal carcinomas in CD so far reported occurred in the past 6.5 years. It would seem as if the risk of colorectal carcinoma in Crohn's colitis has increased in later years.

1) Reports on cancer frequency in UC based on old histopathologic records should be subjected to critical histologic re-evaluation; 2) carcinoma in Crohn's colitis has increased at this hospital, particularly since 1990; 3) the surveillance program strategy used in patients with long-standing UC at this hospital should also embrace patients with Crohn's colitis.