By Jordan Dunitz, MD and Joanne Billings MD, MPH — Adult CF Center, University of Minnesota
- All CF patients are recommended to have a colonoscopy by age 40 (or 5 years post transplant whichever comes first).
- CF patients need a better colon prep (due to stickier stools).
- Doctors need to be aware to check the right side of the colon (and check entire thoroughly) as CF patients’ polyps tend to favour the right side.
Everyone who is touched by cystic fibrosis (CF) – including patients, families and care teams – is encouraged by the dramatic improvement in survival that has occurred in the past few decades. Most patients now live to adulthood, and many to middle and even old age. With improved survival, it is important to anticipate new health challenges that CF patients may face with advancing age. One such concern is colon polyps and colon cancer. From the 1960s to 1990s there were a number of individual cases of cancer reported in CF patients. In 1995, an analysis of large databases including CF patients from the US, Canada and Europe revealed an increase in cancers of the gastrointestinal (GI) tract including esophagus, pancreas and intestines. More recently there have been numerous reports of colon cancer in CF patients.
The risk appears to further increase after lung transplantation. In people without CF, periodic colonoscopy is recommended starting at age 50 in order to identify and remove colon polyps. Polyps are thought to be a precursor for colon cancer, and early detection and removal of polyps appears to reduce the risk of developing colon cancer. There is growing evidence that colon polyps and cancer develop earlier in CF patients than the rest of the population. At the University of Minnesota, we have started routine screening colonoscopy in our CF patients starting at age 40. We recently published the results of colonoscopies performed from 2008 – 2015. We had 82 patients who underwent at least one colonoscopy. Half of these patients had at least one polyp. One quarter of the patients had three or more polyps. Three patients had colon cancer. Thirty-two patients underwent repeat colonoscopies one to four years after their first colonoscopy. For those patients who had polyps on their first colonoscopy, 81% had polyps on the repeat procedure.
Half the patients who did not have polyps on their first colonoscopy were found to have polyps on their second colonoscopy. Based on our findings, we recommend that all CF patients who are medically stable undergo periodic colonoscopy starting at age 40. Those patients who have three or more polyps or polyps with advanced histopathology (higher risk of cancer) should have a repeat colonoscopy in one to three years. All other patients should have a repeat colonoscopy in three to five years. For CF patients who have undergone lung transplantation, we recommend the first colonoscopy at age 40 or five years after transplantation, whichever comes first. We recommend that follow-up colonoscopy follows the same guidelines as CF patients who have not undergone transplantation.
While the timing of a colonoscopy is important, the technique is equally important. Prior to a colonoscopy a patient has to complete a “colon prep.” This washes all of the stool out of the colon so the doctor can get a good look at the walls of the colon. Since CF patients tend to have sticky stool, they need a more thorough prep than patients without CF. At the University of Minnesota, we have developed a colon prep that has been quite effective but still tolerable according to our patients (see CF Colon Prep below). If a colonoscopy is recommended and you have CF, please consider reviewing this prep with your doctor. Many of the polyps in CF patients are found in the right side of the colon. It is important that the doctor performing the colonoscopy is aware of this so that your entire colon is thoroughly examined. Our understanding of colon polyps and colon cancers in CF is still evolving. It is unclear if the increase in polyps and cancer are directly related to the cystic fibrosis transmembrane conductance regulator (CFTR), a difference in the bacteria in the CF colon, or some other cause. More research will be required to better understand why CF patients appear to develop polyps and cancer earlier than those patients without CF. As our understanding improves, recommendations for screening may change.