A 33-year-old woman with a 9-year history of ulcerative colitis comes to the office due to concern about her risk of colon cancer. One of her close family friends died recently from this cancer. The patient wants to "undergo all the tests for colon cancer." She has no other comorbid conditions and is under the care of a gastroenterologist who has kept her disease well controlled with sulfasalazine. Compared with sporadic colorectal carcinoma, colorectal malignancy arising in this patient would more likely exhibit which of the following features?
Colitis-associated vs sporadic colorectal cancer | ||
Colitis-associated | Sporadic | |
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APC = adenomatous polyposis coli; CD = Crohn disease. | ||
Inflammatory bowel disease (IBD) is associated with a significant risk for colorectal carcinoma (CRC); up to 30% of patients with IBD develop CRC in their lifetime. Patients with ulcerative colitis, particularly pancolitis, are at highest risk. Colitis-associated colorectal cancer (CA-CRC) occurs in areas of chronic inflammation, and the risk is proportionate to the duration and severity of inflammation.
(Choices A, B, and D) Unlike sporadic CRC, which typically progresses slowly from a singular dysplastic polyp, CA-CRC is typically more aggressive, often evolves from flat (nonpolypoid) lesions, and is frequently multifocal (ie, multiple synchronous carcinomas) at diagnosis. CA-CRC often affects a younger population than sporadic CRC. These malignancies are more likely to have a higher histopathologic grade, with poorly differentiated or anaplastic cells and a high number of mucinous or signet ring cells. The molecular pathogenesis of CA-CRC is also different than that of sporadic disease, with p53 mutations occurring early in the course of malignant development and APC mutations occurring much later.
Given the high risk for CRC and the difficulty of colonoscopic visualization of flat or multifocal lesions, it is important to regularly monitor IBD via colonoscopy with random biopsies.
Educational objective:
Inflammatory bowel disease, especially ulcerative pancolitis, is associated with a significant risk for colorectal carcinoma. Compared with sporadic colorectal cancer, colitis-associated colorectal cancer is more likely to occur at a younger age, is typically more aggressive with a higher histopathologic grade, often evolves from flat (nonpolypoid) lesions, and is frequently multifocal. Patients should be monitored regularly via colonoscopy with random biopsies.