Inflammatory Bowel Disease and Bowel Cancer: What Is the Real Risk?

Inflammatory Bowel Disease (IBD) is a long-term condition that causes inflammation in the digestive tract. It mainly includes ulcerative colitis and Crohn’s disease. A common and understandable concern after an IBD diagnosis is whether it can lead to cancer.

The short answer is yes, IBD can increase the risk of certain cancers, especially colorectal (colon and rectal) cancer. However, the overall risk is lower than many people fear, and modern treatment and regular monitoring have dramatically improved outcomes.

Why Does IBD Increase Cancer Risk?

Inflammation is the body’s natural response to injury or infection. In IBD, inflammation does not switch off. When the colon remains inflamed for many years, the lining of the bowel can become damaged.

Over time, this ongoing damage may:

• Change the way cells grow and repair themselves
• Increase the chance of abnormal cell changes
• Raise the risk of cancer developing after many years
• The risk is usually higher in people who:
• Have had IBD for more than 8–10 years
• Have inflammation affecting large portions of the colon
• Have poorly controlled or severe inflammation
• Have a family history of colorectal cancer
• Have primary sclerosing cholangitis (PSC), a liver condition linked to IBD
• The longer and more severe the inflammation, the greater the risk.

Types of Cancer Linked to IBD:

1. Colorectal Cancer

Colorectal cancer is the most well-known cancer linked to IBD. Ulcerative colitis generally carries a slightly higher risk, but Crohn’s disease affecting the colon also increases risk.

In the past, the risk was much higher. Today, because of better medicines and routine colonoscopy screening, the number of IBD-related colon cancers has gone down drastically in many parts of the world.

2. Small Bowel Cancer

Small bowel cancer is rare in the general population. However, people with Crohn’s disease affecting the small intestine have a slightly higher risk than those without IBD. Even so, the overall chance remains low. One should become more alert if symptoms suddenly worsen or change.

3. Anal Cancer

People with long-standing Crohn’s disease around the anal area, especially those with chronic fistulas (abnormal tunnels near the anus), may have a slightly increased risk of anal cancer. This is uncommon but requires careful follow-up.

4. Lymphoma and Skin Cancer (Medication-Related)

Some medicines, which are used to control IBD, reduce the activity of the immune system. A few of these drugs have been linked to a small increase in the risk of lymphoma (a cancer of the lymph system) and non-melanoma skin cancers.

It is important to understand that the overall or absolute risk linked to these medications remains small. Doctors carefully evaluate each person’s individual risk factors before prescribing treatment and monitor them regularly during therapy. In most cases, the benefits of keeping inflammation under control are far greater than the potential risks associated with the medicines. In fact, poorly controlled or ongoing inflammation itself can increase the chances of complications, including a higher risk of cancer over time.

The Importance of Regular Screening

Screening is one of the most powerful tools for preventing cancer in people with IBD.

For people with IBD that affects the colon, screening usually begins with a colonoscopy about 8–10 years after diagnosis. After that, the test is typically repeated every one to three years, depending on risk factors such as the extent and severity of inflammation. During a colonoscopy, the lining of the bowel is carefully examined to look for early changes that could develop into cancer. They may also take small tissue samples, known as biopsies, to check for abnormal or precancerous cells.

Finding these changes early means they can be treated before cancer develops. This is one major reason why colorectal cancer rates in IBD have decreased over recent decades.

Can IBD Symptoms Be Confused With Other Conditions?

Some digestive symptoms, such as abdominal pain, bloating, or diarrhea, can overlap with Irritable Bowel Syndrome (IBS). Unlike IBD, IBS does not cause inflammation and does not increase cancer risk.

If symptoms are ongoing or severe, proper medical evaluation is important to confirm the diagnosis and guide monitoring.

What You Can Do to Lower Your Risk

While cancer risk cannot be completely eliminated, it can be reduced significantly with the right steps:

• Take prescribed medicines regularly
• Keep inflammation under control
• Attend all scheduled screenings
• Report new or worsening symptoms early
• Avoid smoking (especially important in Crohn’s disease)
• Use sun protection if on immune-suppressing medicines
• Maintain a healthy weight and balanced diet

Warning Signs That Should Not Be Ignored

Certain symptoms need prompt medical attention:

• Unexplained weight loss
• Persistent or worsening abdominal pain
• New or increasing blood in the stool
• Ongoing fatigue
• Changes in bowel habits lasting several weeks

These symptoms do not automatically mean cancer, but they should always be taken into the consideration.

A Balanced and Reassuring Perspective

Though IBD increases the risk of colorectal cancer. It is considered one of the important risk conditions for colon cancer after certain inherited syndromes. However, the overall risk today is much lower than in the past due to improved treatments and regular monitoring. Most people with IBD live full, healthy lives and never develop cancer. Early diagnosis, proper treatment, and routine follow-up make a meaningful difference.