Who and how to screen for cancer in at-risk inflammatory bowel disease patients

Abstract

Inflammatory bowel diseases (IBDs) include both Crohn’s disease and ulcerative colitis and both diseases are marked by inflammation within the gastrointestinal tract. Due to long-standing inflammation, IBD patients are at increased risk of colorectal cancer, especially patients with chronic inflammation, pancolitis, co-diagnosis of primary sclerosing cholangitis and a longer duration of disease. Small bowel inflammation places Crohn’s patients at an increased risk of small bowel cancer. A higher risk of skin cancers, lymphomas and cervical abnormalities is also seen in IBD patients; this is likely related to both disease factors and the presence of immunosuppressive medication. This article reviews which patients are at an increased risk of IBD-associated or IBD treatment-associated cancers, when to begin screening and which screening methods are recommended.

Keywords:

• biologics
• colorectal cancer
• Crohn’s disease
• IBD-associated cancer
• inflammatory bowel disease
• lymphoma
• skin cancer
• thiopurines
• ulcerative colitis

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• The risk of colorectal cancer (CRC) in ulcerative colitis and Crohn’s disease (CD) patients is increased compared to the general population with additional risk factors, including chronic inflammation, greater disease duration and extent, family history of CRC, and a co-diagnosis of primary sclerosing cholangitis (PSC).

• Colonoscopic surveillance commencing after 8–10 years of disease and recurring every 1–2 years thereafter with random four-quadrant biopsies every 10 cm as well as targeted biopsies has been shown to decrease the risk of CRC in inflammatory bowel disease (IBD) patients.

• IBD–PSC co-diagnosed patients require immediate surveillance at the time of diagnosis and then yearly due to a 10-fold increased risk of CRC.

• Standard white light endoscopy has been the standard for many years, but is now being replaced by high-definition white light. Chromoendoscopy has been shown to increase dysplasia detection and is recommended as a surveillance alternative for practitioners with experience in this technique.

• Although the absolute risk is still low, there is at least a 10-fold increased risk of small bowel cancer in CD patients with small bowel involvement; radiological advances with CT or MR enterography and capsule endoscopy offer possible screening tools.

• Biliary cancer is greatly increased in IBD–PSC patients, although no screening guidelines currently exist aside from a high clinical suspicion and consideration of yearly magnetic resonance cholangiopancreatography with or without the CA 19–9 serum marker.

• Skin cancers, especially nonmelanoma skin cancers, are increased in IBD patients, especially in CD patients and patients on thiopurine therapy; guidelines recommend yearly full skin examinations and if applicable, the patient should be seen by dermatology, sun protective clothing, and sunscreen for IBD patients, especially those on immunosuppressants.

• The risk of lymphoma is increased in IBD patients on thiopurine therapy for at least 1 year with the highest risk in patients older than 50; a high clinical suspicion is needed for early diagnosis.

• Cervical abnormalities, including cervical cancers, are increased in IBD patients on thiopurines and steroids as well as smokers; yearly Pap smear examinations are recommended.