Malignancies in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder, primarily of, but not restricted to, the gut. Association between IBD and cancer has been clearly established and is uniformly accepted.

IBD patients are at particular risk for intestinal and extraintestinal cancers. There are 2 underlying mechanisms: (1) IBD-related inflammation triggers initiation and progression of tumor formation. This particularly results in the development of colorectal cancer, small bowel adenocarcinoma, intestinal lymphoma, anal cancer, and cholangiocarcinoma. (2) Immunosuppressive drugs exhibit carcinogenic properties such as shown for azathioprine and anti-TNF promoting lymphoproliferative malignancies and melanoma and nonmelanoma skin cancer. However, within the last years, IBD-related cancer incidence and prevalence have been decreasing, which might be attributed to better treatment options and surveillance strategies. Moreover, novel biological drugs have been introduced in clinical practice and have dramatically changed long-term IBD management. Therefore, we sought to summarize up-to-date knowledge about (1) overall cancer risk; (2) risk and protective factors for cancer development; and (3) inflammation- and immunosuppression-related malignancies in the current anti-TNF era of IBD. Key Messages: Recent studies and meta-analyses questioned the excess rates of cancer in IBD patients. However, IBD still is associated with cancer development due to ongoing intestinal inflammation and the use of potential carcinogenic drugs. Patients should be educated about the increased risk of cancer with IBD and IBD drugs. However, they should also be informed that most malignancy subtypes are possibly preventable by controlling intestinal inflammation and by using adequate screening strategies.