Danny Kucharsky

October 17, 2007

October 17, 2007 (Philadelphia) — Mesalamine use in patients with inflammatory bowel disease (IBD) is associated with a significant risk reduction in colorectal cancer, a single-center study presented here at the American College of Gastroenterology 2007 Annual Scientific Meeting and Postgraduate Course has found.

Jeffrey Tang, MD, from the department of internal medicine, division of gastroenterology, at Henry Ford Hospital in Detroit, Michigan, presented the retrospective, case-control study that included all patients previously diagnosed with IBD who subsequently developed colorectal cancer at Henry Ford Hospital between January 1970 and December 2005. Data were obtained through chart review.

The study looked at 1784 patients with IBD and found 30 patients with colorectal cancer, 25 of whom had ulcerative colitis. Eighteen of these patients were matched with 1 or 2 control subjects, and 12 were not matched to any controls. Of the 18 patients matched, 15 of them were previously diagnosed with ulcerative colitis. There was no significant difference between cases and controls in terms of sex, race, type of IBD, age at diagnosis, disease duration, family history of IBD, and body mass index.

The researchers found that a total cumulative daily dose of mesalamine of 4500 mg or more for patients with IBD led to a risk reduction for colorectal cancer of 91% ( P = .04), compared with the risk for IBD patients who were matched for other risk factors. The study also found that a cumulative daily mesalamine dose of 4500 mg or more led to a reduction in risk for colorectal cancer of 89% in patients with ulcerative colitis.

There were both strengths and weaknesses in the study, Dr. Tang noted. Its strengths include a long duration of follow-up — 8 years on average for the colorectal cancer group and 12 years for the control group — and a large, diverse population of patients under a single health system.

However, "we were limited by the size of our study — we only found 30 patients with colorectal cancer and ended up only studying 18 of them [compared with] 30 controls," Dr. Tang told attendees during his presentation. "Of course, we also had the limitations of medical record accuracy."

Although mesalamine appears to be a "very promising chemoprotective agent" against colorectal cancer, more research is needed to further evaluate its chemoprotective abilities, Dr. Tang noted.

"The potential clinical implications are great because we know that dysplasia in cancer is a big concern in patients with IBD," commented Carol Burke, MD, a gastroenterologist at the Cleveland Clinic in Ohio, who moderated the session. Although a few epidemiologic and case-control studies have suggested that either mesalamine or folate is effective in reducing the risk of colorectal cancer in patients with IBD, the strength of the association in this study is greater, Dr. Burke said.

However, she added that the study has limitations, including the facts that it is retrospective, it is unclear whether mesalamine doses less than 4500 mg may be effective, and it is unclear whether patients were compliant. Dr. Burke continued, "Although medications were listed in the chart, it doesn't necessarily mean that patients are taking those medications."

If questions about dose, compliance, and disease activity can be answered and "these results reproduced, [then] I think that we have great potential to decrease the burden of cancer in IBD."

The study did not receive external funding. Dr. Tang has disclosed no relevant financial relationships.

American College of Gastroenterology 2007 Annual Scientific Meeting and Postgraduate Course: Abstract 5. Presented October 15, 2007.

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