Introduction

Our digestive system consists of various organs, one of which is the large intestine, commonly known as the colon. The end of the colon, where waste is stored, is called the rectum. Ulcerative colitis (UC) is a condition characterised by the formation of tiny ulcers on the lining of the colon. Blood or pus can often ooze out of these ulcers, which causes pain and discomfort in patients.¹

Most cases of UC can be controlled with regular intake of medicines. However, in severe cases, a J-pouch surgery or ileal pouch-anal anastomosis (IPAA) surgery is necessary this surgery, the colon is removed and a pouch is created inside the body to help the patient pass stools. Additionally, this procedure is performed on patients who have colon or rectal cancer or who are at a high risk of developing these cancers. If an infection develops in the pouch post-surgery, the patient is diagnosed with Pouchitis.²

In this article, we will learn more about pouchitis and whether people with this condition are at high risk of developing cancer.

What is pouchitis?

As discussed earlier, IPAA is a treatment strategy for people suffering from conditions like UC or familial adenomatous polyposis (FAP). Doctors remove their large intestine and create a pouch in the body. Some patients might experience swelling or inflammation in the lining of these pouches, where this condition is called pouchitis.³

Pouchitis affects nearly 60% of UC patients post-IPAA surgery, making it the most common post-surgery complication. However, it is worth noting that pouchitis is rare among patients with FAP who undergo surgery.

Types

Based on how long the symptoms persist, their frequency, and how the patients respond to medication, pouchitis is divided into various types.

• Acute pouchitis is when the patients experience mild symptoms and the condition does not persist for more than 4 weeks
• Chronic pouchitis occurs when patients experience severe symptoms that last longer than four weeks despite medication, or when the pouchitis reoccurs despite treatment
• If the patient’s condition improves or gets cured with antibiotics, they’re said to have responsive pouchitis
• If the patient is not responding to medication, they’re said to have refractory pouchitis

Chronic pouchitis is a rare condition and is known to cause a lot of pain and discomfort for the patients.⁴

Causes and symptoms

The human body is a host for various types of bacteria. A type of bacteria, gut bacteria, is beneficial and resides in our intestines. Researchers believe that when a patient undergoes the J-pouch surgery, the bacteria in their small intestine are exposed to the bacteria in their large intestine. This exposure may cause an immune reaction and confuse the body into thinking that they are infected. As such, this causes inflammation or swelling in the pouch. Researchers are yet to discover if the immune reaction is caused by the overgrowth of the gut bacteria that are already present in the body, or if it is due to a new pathogenic bacterium that might enter after the surgery is performed.^4,5

Some of the most common symptoms experienced by patients with pouchitis are:

• Lower abdominal pain or cramping
• Increase in the frequency of passing stools
• Losing control over one’s bowel movements, which results in the leaking of stools.
• Traces of blood in stools
• Fever
• Experiencing difficulty or pain when passing stools

Acute Pouchitis is common among UC patients post-surgery, and the condition can be cured with the intake of antibiotics. However, there are greater risks associated with chronic pouchitis.⁵

Understanding CARP and dysplasia

Chronic antibiotic-resistant pouchitis (CARP) occurs when a patient with pouchitis does not improve with antibiotic treatment or no longer responds to antibiotics as well as they did previously. This might occur due to various reasons, like some structural defect in the pouch, infection, or if the patient is suffering from an autoimmune disease.⁵ Patients suffering from CARP are most likely to experience long-term inflammation in the pouch.

Dysplasia is defined as abnormal growth or differentiation of cells. Researchers believe that dysplasia acts as a warning sign for cancer, as it is also characterised by uncontrolled cell growth. Long-term inflammation of the ileal pouch can cause dysplasia in the cells lining the pouch. If abnormalities in cell growth are not very significant, the dysplasia is said to be mild, and it is less likely that those cells will become cancerous. If the dysplasia is severe, then there’s a high risk of developing cancer.⁶

Pouch dysplasia and cancer: What does the evidence say?

As stated earlier, chronic inflammation and dysplasia are linked to cancer. But is there any compelling evidence linking the two in the case of pouch dysplasia? Are all patients with chronic pouchitis at high risk of developing colorectal cancer? Let’s dive deep into it.

Researchers have performed various studies over the years to determine the likelihood of pouch dysplasia developing into cancer. A study by Vento et al. (2011) evaluated 42 patients with chronic pouchitis over a median follow-up of 8.3 years. While none of the pouch biopsies showed dysplasia, one patient developed adenocarcinoma at the anal anastomosis. The study concluded that, although dysplastic changes were not detected during the first decade after surgery, a small risk of cancer remains at the anal anastomosis, suggesting the need for focused follow-up in at-risk groups.⁷

Nilubol et al. evaluated the incidence of mucosal dysplasia in patients who underwent IPAA. They assessed the outcome of their study based on the pouch biopsy results and observed that the inflammation in the pouch was common among the subjects; only 1 among the 138 patients developed mucosal dysplasia.⁸

Similarly, a study by Börjesson et al. (2004) found that dysplastic transformation within the ileal pouch mucosa in patients who had surgery for ulcerative proctocolitis is rare, even after long-term follow-up. The results were considered reassuring for both patients and surgeons, indicating no solid grounds to support routine surveillance for dysplasia in the ileal pouch mucosa in these patients.⁹

Conclusion

Although pouchitis is common among UC patients who have undergone the J-pouch surgery (60%), most cases are acute and can be managed by prescribing medication.⁴ However, chronic pouchitis is rare and difficult to manage. It often requires the use of specialised medication like corticosteroids, immunosuppressants, and mesalamine enemas to be kept under control.⁵ If pouchitis keeps relapsing or the patient stops responding to treatment, it might lead to prolonged inflammation of the pouch. This long-term inflammation may lead to complications like pouch dysplasia.

Evidence from various studies indicates there is a link between chronic inflammation, dysplasia and the subsequent development of adenocarcinoma. However, the prevalence of dysplasia among patients with chronic pouchitis is extremely rare, with signs typically appearing only ten years after surgery.7-9 However,  more long-term research with a larger number of subjects is needed to attain the exact data on this.

While dysplasia is uncommon, it doesn't mean that individuals with chronic pouchitis are exempt from developing cancer.  Therefore, people with acute pouchitis must make adequate changes in their lifestyle to prevent the onset of chronic pouchitis. Additionally, patients with chronic pouchitis must get themselves checked regularly for dysplasia or other signs of inflammation to reduce the risk of cancer.

Pouchitis can be controlled by regular administration of antibiotics, probiotics, and consumption of an antioxidant-rich diet. ⁵ It is important to screen patients with risk factors regularly and do more research on the long-term effects of chronic pouchitis to eliminate the complications associated with this condition.