How Do You Screen and Survey for Dysplasia in Crohn’s Patients? Can You Perform Segmental Resection in Crohn’s Patients With Dysplasia?
Population- and hospital-based studies that span at least 35 years support an increased risk of colon cancer in patients with Crohn’s disease (CD). Many of these papers, however, do not separate out the patients who are specifically at risk (those with extensive Crohn’s colitis). One cannot compare the risk for colorectal cancer in CD with that of ulcerative colitis (UC) unless patients with equal extent and duration of disease are studied. Patients with only ileal disease or gastroduodenal disease have never been shown to have an increased risk of colorectal cancer. In studies that looked specifically at the risk of colorectal cancer in patients with Crohn’s colitis, the standardized incidence ratio or the relative risk (RR), depending upon the study, is anywhere from 0.8 to 23.8.1,2 In the only published surveillance program of 259 patients with Crohn’s colitis,3 there was a 22% chance of developing any low-grade dysplasia (LGD), high-grade dysplasia (HGD), or cancer by the fourth surveillance colonoscopy. Ninety percent of the patients in this study had extensive colitis, but all had more than a third of the colon involved. A recent study that followed the same group of patients for another 7 years reported a 25% chance of developing LGD, HGD, or cancer by the 10th surveillance exam, and a 7% chance of developing flat HGD or cancer by the 10th surveillance exam (Figure 19-1). There were 14 cancers found in this study—three on the screening exam and 11 on the surveillance exam or at surgery.4 This is significantly more than is reported in the SEER (Surveillance, Epidemiology and End Results) registry as the number of cases of colorectal cancer that are expected in the general population (1.13).5
Figure 19-1. Cumulative probability of an initial finding of dysplasia or cancer on surveillance exams. CA = cancer. This figure was published in Clin Gastroenterol Hepatol. Friedman S, Rubin D, Bodian C, Harpaz N, Present DH. Screening and surveillance and surveillance colonoscopy in chronic colitis: results of a surveillance program spanning 25 years. 953-954. Copyright Elsevier (2008).
Given the increased incidence of colorectal cancer in Crohn’s colitis, we do need to perform colonoscopic surveillance in these patients. I recommend an initial screening colonoscopy at 8 years after onset of symptoms in patients with at least one-third of the colon macroscopically or microscopically involved. Those patients at a higher risk for cancer have a large extent of disease (pancolitis), longer duration of disease, colonic strictures that are impassable with a pediatric colonoscope, and surgically bypassed segments of the colon. Other factors that further increase the risk of colorectal cancer are a personal history of primary sclerosing cholangitis, a family history of colon cancer, and a young age of disease onset. At screening colonoscopy, 4 quadrant biopsies should be performed every 10 cm, and biopsies should also be taken from strictures, suspicious lesions, and masses. All polypoid dysplastic lesions deemed “adenoma-like” can be totally removed. The bases of all polyps should be biopsied extensively, as well as the areas of mucosa surrounding each polyp. If endoscopy and pathology are negative, the exam should be repeated in 2 years.
If dysplasia is found, management is controversial. There is little hard data on the management of dysplasia and cancer in Crohn’s colitis, and new imaging techniques such as dye spray, magnification, and high definition colonoscopy are unstudied in CD. For unifocal flat LGD in Crohn’s colitis, the management is even more difficult than in UC. Many patients with Crohn’s colitis have extensive ileal disease, and surgery would involve an extensive ileal resection, as well as a total proctocolectomy and standard Brooke ileostomy. This might predispose a patient to short bowel syndrome or, at the very least, trouble with fluid balance. Since doctors and patients alike are reluctant to choose such an extensive surgery, frequent surveillance is often more palatable. An alternative management would be to do another colonoscopy in 1 to 6 months with dye spray and a high-definition colonoscope. If recurrent or multifocal LGD is found, the patient will need surgery after confirming the results with a second pathologist. The usual surgeries performed for flat LGD are a total proctocolectomy and ileostomy, or a subtotal colectomy and ileo-rectal anastamosis. This latter surgery can be performed, of course, only if the dysplasia is not located in the rectum and as long as there is no active perianal fistulizing disease.
Flat HGD is a more serious lesion than flat LGD, and there is a higher likelihood of cancer elsewhere in the colon. If the location cannot be definitely ascertained, the patient will need an extensive resection. If the HGD occurs within a mass, and if there is no dysplasia elsewhere in the colon, a segmental resection can be considered. Before doing a segmental resection, however, it would be prudent to do another colonoscopy with dye spray and a high-definition colonoscope to make sure there is no other dysplasia. With this said, I would discuss with the patient that dysplasia usually occurs as a field effect, and where there is one lesion, there will likely be others in the future. For a mass containing cancer, the same principle would apply. In a patient with no microscopic or macroscopic CD elsewhere in the colon, it is probably safe to do a segmental resection. For a patient with pancolitis, it is less safe but reasonable to perform in a patient with extensive ileal disease or in a medically less fit patient who cannot tolerate major surgery. In one study, 3 patients with cancer had segmental resections even though they had pancolitis.4 Five-year follow-up has been negative for recurrent dysplasia or cancer.
The management of polyps is exactly as in UC. Pedunculated polyps containing LGD, HGD, or cancer can be removed by snare cautery and followed by surveillance colonoscopies. Small sessile LGD polyps can be removed endoscopically, but consideration should be given to surgery in patients with large sessile polyps that are difficult to remove or smaller sessile polyps containing HGD or cancer.
For the field of management of dysplasia in chronic Crohn’s colitis, the waters are almost uncharted. There is only a single study of a colonoscopic surveillance program spanning 25 years, but the results are by no means definitive. What makes Crohn’s complicated is the extensive ileal disease and active perianal disease that these patients often have, making surgery less feasible. It is likely that with new technology, including chromoendoscopy, magnification endoscopy, and high-definition endoscopy, surgery will be performed less and less for LGD in CD. What is most important is that the same rules of surveillance apply for Crohn’s as in UC—that patients with more than 8 years of disease duration and more than half of the colon involved undergo biennial colonoscopic surveillance.
1. Gyde SN, Prior P, Macartney JC, et al. Malignancy in Crohn’s disease. Gut. 1980;21(12):1024-1029.
2. Jess T, Loftus E, Velayos F, et al. Risk of intestinal cancer in inflammatory bowel disease: a population-based study from Olmstead, Minnesota. Gastroenterology. 2006;130(4):1039-1046.
3. Friedman S, Rubin PH, Bodian C, Harpaz N, Present DH. Screening and surveillance colonoscopy on chronic Crohn’s colitis. Gastroenterology. 2001;120(4):820-826.
4. Friedman S, Rubin PH, Bodian C, Harpaz N, Present DH. Screening and surveillance colonoscopy in chronic Crohn’s colitis: results of a surveillance program spanning 25 years. Clin Gastroenterol Hepatol. 2008;6(9):993-998.
5. Ries LAG, Melbert D, Krapcho M, et al, eds. SEER Cancer Statistics Review, 1975-2004. Bethesda, MD: National Cancer Institute; 2007. Available at: http://seer.cancer.gov/csr/1975_2004/. Based on November 2006 SEER data submission, posted to the SEER web site, 2007.