Some IBD Drugs May Raise Skin Cancer Risk
Study Shows Increased Risk for Patients Taking Immune-Suppressing Medications
Oct. 26, 2009 -- Patients with inflammatory bowel disease or IBD may be at an increased risk for getting skin cancer, according to a study presented at the American College of Gastroenterology's annual meeting in San Diego.
The risk appears to be linked to medications to control IBD, says researcher Millie Long, MD, MPH, at the University of North Carolina, Chapel Hill.
And some medications boost risk more than others, she found.
''Patients on immunosuppressant medications, particularly of the thiopurine class, have an increased risk of skin cancer, greater than three times, compared to patients with IBD who do not use these medications," Long tells WebMD. Purinethol and Imuran are examples of thiopurines.
While previous research by others has also found an increased risk of skin cancer in IBD patients, Long says her study is thought to be one of the first to zero in on specific medications.
For the study, Long and her colleagues first looked at the records of 26,403 IBD patients with Crohn's disease and 26,974 with ulcerative colitis, evaluating their records from 1996 through 2005. Each of the patients was matched according to age, sex, and region of the country with records from three patients who did not have IBD.
IBD is used to refer to both ulcerative colitis and Crohn's disease. While different parts of the gastrointestinal tract are usually affected, both diseases involve chronic inflammation, resulting in symptoms such as diarrhea, rectal bleeding, and abdominal cramps. (IBD is different than IBS or irritable bowel syndrome, which does not involve intestinal inflammation or damage.)
The cause of IBD isn't known, but experts say it is related to the immune system responding to the body inappropriately.
Overall, Long found that the risk of getting a nonmelanoma skin cancer was 1.6 times higher for the IBD patients than patients in the comparison group.
Nonmelanoma skin cancers include squamous cell and basal cell skin cancers. About 1 million people in the U.S. are diagnosed annually with these cancers, which are extremely curable if detected early.
IBD Patients Only
Long's team took a closer look at just the IBD patients in the study and the specific medicines they took. Several types of medications are used to treat IBD, with a goal of decreasing excess activity of the immune system. Long compared 742 IBD patients with skin cancer to 2,968 IBD patients without skin cancer.