Crohn’s disease can cause inflammation in your gastrointestinal tract that may increase your risk of cancer. Immunosuppressant medications used to treat Crohn’s might also increase your risk.

Crohn’s disease is a form of inflammatory bowel disease (IBD) that can cause inflammation throughout your digestive tract. It usually affects your small intestines and the beginning of your large intestines but can cause inflammation anywhere between your mouth and your anus.

Inflammation in people with Crohn’s disease can potentially lead to increased cell turnover in the gastrointestinal tract. And this can increase the risk of gene mutations that lead to cancer.

Medications that decrease your immune system activity are the primary treatment for Crohn’s disease. As an undesired consequence, these medications might also impair your immune system’s ability to identify and destroy cancer cells.

This article takes a closer look at the connection between Crohn’s disease and cancer.

Studies consistently suggest that people with Crohn’s disease may be at an increased risk of intestinal and other cancers compared with people without Crohn’s disease.

Chronic inflammation in your intestines can lead to increased turnover of cells, which can potentially increase the risk of genetic mutations. Some mutations can cause cells to replicate out of control, leading to the development of cancer cells.

One job of the immune system is to target and destroy cancer cells. However, the immunosuppressant medications used to treat Crohn’s disease might contribute to the development of cancer by decreasing immune activity.

Many studies report a 2 to 3 times increased risk of colorectal cancer in people with Crohn’s disease. However, the exact value varies depending on factors such as the methodology and population in the study.

It’s worth noting that the risk of colorectal cancer depends on whether there is involvement in more than one-third of the colon. If there is no colon involvement or less than one-third involvement, then the risk of colon cancer is very low.

In a 2023 study from Norway, researchers found that Crohn’s disease was associated with a 1.56 times (95% CI: 1.06 to 2.28) increased cancer risk in people with Crohn’s disease compared with people without it. The trend was stronger for males than females.

One type of cancer that develops in your small intestines is called adenocarcinoma. Although this type of cancer is rare, the risk of small-bowel adenocarcinoma may be as much as 30 times higher in people with Crohn’s disease than in people without Crohn’s disease.

Along with cancers of the small and large intestine (such as adenocarcinoma and colorectal cancer), people with Crohn’s disease may have an increased risk of cancer in general.

Crohn’s disease has been associated with many different types of cancer, with varying degrees of evidence supporting these connections.

Types of cancer Crohn’s disease has been linked to include:

What are the symptoms of colorectal cancer?

Crohn’s disease is most associated with colorectal cancer. Symptoms of colorectal cancer can include:

Cancer that develops in your small intestines can cause similar symptoms. It’s important to consult your doctor any time you develop unexplained GI symptoms that are persistent or continue to get worse.

Research linking Crohn’s disease to breast cancer is mixed.

In a 2024 study, researchers found that a genetic susceptibility to IBD was associated with a small increased risk of breast cancer. Conversely, breast cancer was associated with an elevated risk of developing IBD.

Some research has found that Crohn’s disease may be linked to a lower risk of breast cancer.

In a 2023 study, researchers examined the incidence of breast cancer among 70,027 people with and without Crohn’s disease. The researchers reported that people without Crohn’s disease had an increased prevalence of breast cancer throughout all age ranges.

Even though people with Crohn’s disease seem to be at an increased risk of cancer, many people with Crohn’s disease never go on to develop cancer.

Keeping your Crohn’s disease under good control can potentially help you reduce inflammation in your GI tract. This may help prevent cellular damage that may cause cancerous changes in the lining of your intestines.

Receiving regular colonoscopies can help doctors detect cancerous changes in your colon early and catch the cancer before it spreads.

Most guidelines recommend an initial screening colonoscopy with staging biopsies 8 years after symptom onset for everybody with IBD, if one-third or more of the colon is involved.

People with Crohn’s disease seem to be at an increased risk of cancer compared with people without Crohn’s disease. They seem to be at a higher risk of small and large intestinal cancer (colorectal cancer). But Crohn’s disease has also been linked to other types of cancer.

It’s important to follow your doctor’s screening guidelines for colorectal cancer, especially if you have Crohn’s disease. Undergoing regular colonoscopies can help you catch cancer when it’s easiest to treat and you have the best outlook.