Why Can Long-Term IBD Increase Colorectal Cancer Risk?
IBD causes ongoing or recurring inflammation that damages the lining of the colon or other portions of the digestive tract. As these damaged cells are replaced over many years, errors can occur in the process of cell repair and renewal, increasing the likelihood of abnormal changes known as dysplasia.
Dysplasia refers to abnormal cells that are not yet cancerous but have the potential to develop into cancer. Controlling inflammation through IBD treatment helps limit ongoing damage to the colon and reduce the risk of long-term complications.
What Factors Increase Colorectal Cancer Risk in People With IBD?
The risk of colorectal cancer varies among people with IBD. Doctors assess several factors to determine who requires closer monitoring and when regular colonoscopy surveillance should begin.
Disease Duration and Cumulative Inflammation
The longer inflammation affects the colon, the more opportunities there are for damage to accumulate in its lining. People with IBD who experience persistent or frequently recurring inflammation over many years generally face a greater colorectal cancer risk.
This risk becomes more significant after approximately 8–10 years of colonic IBD, making disease duration an important factor in determining when regular colonoscopy surveillance should begin.
Extent and Location of Inflammation
The amount of the colon affected by inflammation also influences colorectal cancer risk. Widespread inflammation exposes more of the bowel lining to repeated injury and increases the area in which abnormal cell changes can develop.
For example, ulcerative colitis affecting much of the colon generally carries a higher colorectal cancer risk than disease confined to the rectum. Similarly, Crohn's disease involving the colon is associated with increased risk, while Crohn's disease limited to the small intestine does not carry the same additional colorectal cancer risk.
Additional Medical and Family Risk Factors
Certain medical conditions and personal or family history can indicate a higher colorectal cancer risk in people with IBD.
These include primary sclerosing cholangitis (PSC), a condition affecting the bile ducts, previous colorectal dysplasia and having a close relative with colorectal cancer. Doctors consider these factors alongside the person's IBD history when determining the need for more frequent surveillance.
How Does Colonoscopy Surveillance Help Manage Long-Term Risk?
Colonoscopy surveillance allows an IBD specialist to examine the colon for precancerous changes before symptoms develop. Identifying these changes early provides an opportunity to remove certain abnormal areas or recommend further treatment before cancer develops.
Early Detection of Precancerous Changes
Dysplasia can develop in the colon without causing noticeable symptoms. Through regular colonoscopy, doctors can identify suspicious areas in the bowel lining and take tissue samples to determine whether abnormal cell changes are present.
Detecting dysplasia before it progresses to cancer creates an opportunity for earlier intervention, including the removal of suitable abnormal areas during colonoscopy.
Identification of Persistent Inflammation
Colonoscopy allows doctors to examine the extent and severity of inflammation in the colon, including inflammation that remains active despite improvements in symptoms.
These findings help determine whether IBD treatment is adequately controlling the disease or requires adjustment. Better control of inflammation helps limit the repeated damage to the colon associated with long-term colorectal cancer risk.
Timely Intervention for High-Risk Findings
Surveillance also helps doctors identify changes that require more intensive follow-up or treatment. For example, dysplasia that cannot be completely removed during colonoscopy, particularly when it is extensive or associated with other high-risk findings, may require surgical assessment.
By identifying these problems before they progress further, doctors can recommend appropriate intervention, including surgery when necessary, to reduce the likelihood of advanced colorectal cancer.
Plan Your Long-Term IBD and Colorectal Cancer Care With Surgical Associates
Managing IBD over the long term involves addressing the potential complications of chronic inflammation, including colorectal cancer. Regular assessment and appropriate surveillance help identify concerning changes early, allowing treatment decisions to be made before more serious complications develop.
At Surgical Associates, we provide assessment and management for IBD and colorectal conditions. Senior Consultant Colorectal Surgeon Dr Tan Wah Siew is able to review your disease history, assess your colorectal cancer risk and advise on appropriate surveillance or further treatment where necessary.
If you have long-standing IBD or concerns about your colorectal cancer risk, contact us to arrange a consultation with Dr Tan and discuss your long-term care needs.
