Colorectal cancer (CRC) is the most common neoplastic complication of UC, with an incidence of 3 per 1,000 person-years of disease and a prevalence of 3–7 % [12]. It is more likely to be multiple, have a higher grade, and be nonpolypoid than sporadic noncolitic cancers.

Particular risk factors for CRC among people with UC are:

Considering all patients with UC, the risk of cancer increases with the duration of the disease:

The risk in the subgroup of those with extensive colitis is significantly greater:

Dysplasia in UC is the most reliable marker of an increased risk of CRC, but it can be difficult to detect. It is divided into four categories:

Dysplasia presents as two main patterns: flat lesions and elevated lesions. Flat dysplasia is often identified incidentally in surveillance biopsies from unremarkable mucosa, although dye-spraying may improve the detection of flat dysplasia. Elevated lesions can be either adenoma-like – essentially sporadic adenomas, as in people without UC – or non-adenoma-like. This latter group is more heterogeneous, the lesions are less demarcated, and the surrounding flat mucosa is more likely to be dysplastic. Hence biopsy of the surrounding mucosa of any elevated lesion in UC is essential. Adenoma-like dysplasia can essentially be treated like any other adenoma if the surrounding mucosa is nondysplastic.

A proctocolectomy with or without ileal pouch formation should be recommended to all patients with the following conditions [13, 14]:

It should also be considered in patients with flat LGD. Patients should be told that their risk of CRC is nine times greater than that in patients without LGD, and the risk increases with a more distal location of the cancer in the colon/rectum. A colectomy with ileorectal anastomosis could in exceptional circumstances be considered in colonic cancer/HGD with careful postoperative surveillance (see below Sect. 14.11.2: Colectomy and ileorectal anastomosis). Given these risks in UC, screening for colorectal cancer is obviously important. Screening guidelines have been developed [15]:

The risk of cholangiocarcinoma is increased in patients with UC on account of the relationship between UC and PSC. About 4 % of patients with UC develop PSC during their lifetime, and in this population the lifetime risk of cholangiocarcinoma is about 10 %. The risk of cholangiocarcinoma, like PSC, is not influenced by the disease activity of UC.

This is a nonobstructive dilatation (>6 cm) of colon in conjunction with extensive colitis (rarely just left-sided disease) and systemic disturbance. The incidence is falling and currently occurs in less than 4 % of patients with UC. Patients are at greatest risk early after diagnosis, especially during the first attack. It often follows a prolonged attack of drug-resistant acute colitis, and hypokalemia, opioid analgesics, drugs causing constipation, anticholinergics, and possibly superadded infections such as Clostridium difficile and cytomegalovirus are believed to be precipitants. Examination reveals mild tympanitic distension, but any evidence of localized or generalized peritonism should be an indication for emergency surgery. Medical management of toxic acute UC is permissible at the first instance (see Sect. 14.7.2.1), but any deterioration or failure to improve should again lead to emergency surgery.

The criteria for diagnosis of toxic megacolon are [17]:

The dilatation is accompanied by and possibly the result of inflammation of the bowel wall extending beyond the mucosa into the muscle. This leaves the bowel prone to perforation, which is why the condition is so dangerous. Perforation of a toxic megacolon carries a mortality of 40 %.

Severe GI bleeding occurs in less than 5 % of all patients with UC but accounts for about 10 % of the emergency colectomies performed for UC [18]. The risk of significant hemorrhage increases with the extent of the disease.

These occur in about 4 % of all patients with UC, predominantly in the left colon. Treatment depends on the degree of symptoms and the extent of disease elsewhere in the colon. Total colectomy is the usual surgical option.

The gold standard for diagnosing colitis is flexible sigmoidoscopy/colonoscopy. This shows acute inflammation starting in the rectum and extending proximally, and allows biopsies to be taken for histology. Care is required because the risk of perforation is high in acute disease, and colonoscopy should be reserved for assessing the extent of disease after the acute attack has been treated. Extent of disease is defined by the Montreal classification (Table 14.3). About 20 % of patients have extensive disease at presentation [19] (Fig. 14.1).

In active disease, the mucosa is erythematous, granular, friable, and demonstrates contact bleeding. Pseudopolyps, which are islands of mucosa within an area of extensive ulceration, may be present in severe disease. In quiescent chronic disease, the mucosa usually shows signs of chronic injury, with loss of the normal vascular pattern, and may appear featureless. Inflammatory polyps may be present.

Biopsies should be taken from multiple sites along the colon (including areas that appear normal), always including the rectum [20]. The contiguous nature of the disease is one of the major features that distinguishes UC from Crohn’s colitis, although this is not always apparent macroscopically. However, even when there is variation in the severity of the colitis between different segments of the bowel, which can give a false impression of skip lesions, biopsies from the apparent “skip” area usually show features of chronic inflammation typical of UC, highlighting the importance of multiple biopsies. In chronic disease and in patients who have received topical therapy, the rectum can often appear normal, giving the impression of rectal sparing. Again, biopsy is crucial in the diagnosis. Another area of confusion is near the ileocecal valve, where the “cecal patch” can give the impression that it is a focus of inflammation distant from a more distal area of colitis and therefore a “skip lesion.” This can be seen even in normal asymptomatic individuals.

Once colitis is established as a cause of the patient’s symptoms, histology and microbiology help confirm the diagnosis of UC.

UC is confined to the large bowel, although up to 30 cm of terminal ileum can be involved with “backwash ileitis.” Reports of biopsies taken during ileocolonoscopy should describe whether the tissue shows features of UC to distinguish it from other common causes of colitis such as Crohn’s disease, pseudomembranous colitis, and diverticular disease. They should also comment on disease activity and on any dysplasia seen within the specimen.

The severity of the inflammatory reaction correlates well with the clinical course of the disease. Cardinal features of UC include:

No evidence that elemental diets or any other treatment other than pharmacological or surgical treatment is of benefit in either the induction or maintenance of remission in UC.

The medical treatment of UC is divided into treatment of acute disease, treatment of chronic active disease, and maintenance of remission. Following ileal pouch formation (see Sect. 14.11.4), patients can develop pouchitis. This is discussed here.

The 2015 European consensus guidelines [14] provide a review of the evidence for surgical decision making in UC. Despite advances in medical treatment, up to 30 % of patients with UC will ultimately require a colectomy. The indications for surgery are:

In both situations there are those who require emergency surgery (eg severe acute colitis not responding to medical treatment (Fig. 14.2), colonic perforation) and those who can have their surgery planned electively.

Emergency surgery involves total colectomy and end ileostomy as a life-saving procedure. Management of the retained rectum is discussed below. Patients presenting with severe acute colitis as their first attack are the most likely to require colectomy (up to 25 %).

Following recovery from a total colectomy, the fate of the remaining rectum must be considered, as it can continue to cause bloody anal discharge if the inflammation fails to subside, and it remains a site of potential cancer, although the risk is about 5 % over 20 years. There are four options for the residual rectum: