Increased Skin Cancer Risk Among Those with Inflammatory Bowel Disease
People with inflammatory bowel disease (IBD) may be at increased risk of non-melanoma skin cancer, particularly if they receive immune-suppressing medications such as thiopurines. These were the results of two studies published in Gastroenterology.
Crohn’s disease and ulcerative colitis are the two major types of IBD. Ulcerative colitis involves inflammation of the lining of the large intestine, and Crohn’s disease involves inflammation of the lining and wall of the small or large intestine. Certain treatments for IBD act by suppressing the immune system, which could increase the risk for certain types of cancer. Immune-suppressing drugs include the thiopurines (e.g. azathioprine and mercaptopurine).
Non-melanoma skin cancer refers to skin cancers other than melanoma. The most common types of non-melanoma skin cancer are basal cell carcinoma and squamous cell carcinoma. These types of skin cancer are less likely than melanoma to be fatal (although some deaths do occur), but they can be disfiguring and invade nearby tissues.
Two studies published in the journal Gastroenterology evaluated the risk of non-melanoma skin cancer among people with IBD. The first study involved more than 9,600 IBD patients who had been identified from the University of Manitoba IBD Epidemiology Database. Risk of skin cancer in these patients was compared with the risk in a similar group of people without IBD.
- People with IBD were 20% more likely to develop basal cell carcinoma than people without IBD.
- Risk of squamous cell carcinoma was increased among IBD patients who used thiopurines.
The second study was conducted in France and involved more than 19,000 people with IBD. 
- Current and past users of thiopurines had an increased risk of non-melanoma skin cancer. This increased risk was seen even among young patients (those under the age of 50).
These results suggest that people with IBD may have an increased risk of nonmelanoma skin cancer, particularly if they use thiopurines. As a precaution, people with IBD should protect their skin from the sun and monitor their skin for any changes. People with IBD may also wish to talk with their doctor about whether periodic skin exams would be appropriate.
 American Gastroenterological Association. Patient brochure: Inflammatory Bowel Disease. April 23, 2010.
 Singh H, Nugent Z, Demers AA, Bernstein CN. Increased risk of nonmelanoma skin cancers among individuals with inflammatory bowel disease. Gastroenterology. 2011;141:1612-20.
 Peyrin-Biroulet L, Khosrotehrani K, Carrat F et al. Increased risk for nonmelanoma skin cancers in patients who receive thiopurines for inflammatory bowel disease. Gastroenterology. 2011;141:1621-28.
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