Colorectal Cancer and Cystic Fibrosis

Advances in the understanding and treatment of cystic fibrosis (CF) have led to longer life expectancies than ever before. This is a positive development within the world of CF. But it does mean that other conditions that tend to show up later in life may be rising in the aging CF population. One of these potentially co-occurring conditions is colorectal cancer.

The overall risk of getting colorectal cancer is increased by 5 to 10 times in those with CF compared to the general population. This risk increases to 20 to 30 times higher for those with CF who have also received an organ transplant.^1-3

What is colorectal cancer?

The term colorectal cancer refers to cancer that starts in either the colon (colon cancer) or rectum (rectal cancer). Colorectal cancer often starts as a small growth (polyp) in the colon or rectum. The growth gets larger and invades the walls of the digestive (gastrointestinal) tract around it.²

But it’s important to note that not all polyps cause colorectal cancer. Many are noncancerous (benign). If your doctor tells you that you have a colorectal polyp, that does not mean that you definitely have colorectal cancer. Your doctor can take a sample of the polyp and send it to a lab to be analyzed. That analysis will help determine what kind of polyp it is.²

If not diagnosed and treated, cancer can progress and invade other structures in the body (metastasize). There are treatment options for colorectal cancer. But this type of cancer can be life-threatening if it is not discovered until later stages. This is why it’s important to undergo regular screening for colorectal cancer, especially if you are at an increased risk.

Not everyone with colon cancer will experience symptoms. Those that do may experience:²

• Blood in the stool
• General abdominal pain
• Changes in bowel habits
• Weight loss

It’s important to let your doctor know as soon as possible if you experience these symptoms.²

Why do people with CF have a higher risk of colorectal cancer?

More information is needed, but there are some theories as to why this occurs. First, some experts believe that the CFTR (cystic fibrosis transmembrane conductance regulator) gene mutation (change) that is common in cystic fibrosis may play a role in the development of colorectal cancer in people with CF.

A higher rate of cell turnover (the rate at which cells die and new ones are created to replace them) in the gastrointestinal system has also been thought to play a role in colorectal cancer among those with CF. Long-term mucus-related obstruction and inflammation within the body may also contribute. Another potential reason for the heightened risk may be the amount of radiation a person with CF is exposed to in the form of CT scans or x-rays, among other procedures.¹

The risk among those with organ transplants may be higher due to immunosuppressive medications required after transplant. When a person’s immune system isn’t working or is suppressed, its ability to recognize and fight potential cancers is decreased. Additionally, those who receive a transplant may have an increased life expectancy. A longer life expectancy may increase the chances of developing cancer later in life.¹

Much more research is needed to fully understand the link between cystic fibrosis and colorectal cancer.

What can people with cystic fibrosis do to decrease their risk?

An important step for anyone, especially those with CF, is to undergo regular screening. This will allow for the earliest possible detection and treatment of a developing cancer.

A colonoscopy is a procedure in which a long, small tube is inserted into the rectum while you are sedated or asleep. The tube has a video camera which is used to look at the rectum and colon. Special tools can be used to remove any polyps during the colonoscopy. Then the polyps are sent to a lab for further review.²

It is recommended for the general population to receive colonoscopies beginning at age 50. But people with CF should be screened starting at 40 years old and every 3 to 5 years after, depending on their specific situation. Those who have had an organ transplant may need to be screened starting at age 30, or within 2 years after transplant.^1-3

Regardless of whether you have had an organ transplant, your doctor can advise you on the best screening schedule for you.