Clinicopathological Characteristics and Surgical Outcomes of Crohn Disease-Associated Colorectal Malignancy.

PURPOSE Carcinoma arising from Crohn disease (CD) is rare, and there is no clear guidance on how to properly screen for at-risk patients and choose appropriate care. This study aimed to evaluate the clinicopathological characteristics, treatment, and oncologic outcomes of CD patients diagnosed with colorectal cancer (CRC). METHODS Using medical records, we retrospectively enrolled a single-center cohort of 823 patients who underwent abdominal surgery for CD between January 2006 and December 2015. CD-associated CRC patients included those with adenocarcinoma, lymphoma, or neuroendocrine tumors of the colon and rectum. RESULTS Nineteen patients (2.3%) underwent abdominal surgery to treat CD-associated CRC. The mean duration of CD in the CD-associated CRC group was significantly longer than that in the benign CD group (124.7 ± 77.7 months vs. 68.9 ± 60.2 months, P = 0.006). The CD-associated CRC group included a higher proportion of patients with a history of perianal disease (73.7% vs. 50.2%, P = 0.035) and colonic location (47.4% vs. 6.5%, P = 0.001). Among 19 CD-associated CRC patients, 17 (89.5%) were diagnosed with adenocarcinoma, and of the 17 cases, 15 (88.2%) were rectal adenocarcinoma. On multivariable analyses for developing CRC, only colonic location was a risk factor (relative risk, 7.735; 95% confidence interval, 2.862-20.903; P = 0.001). CONCLUSION Colorectal malignancy is rare among CD patients, even among patients who undergo abdominal surgery. Rectal adenocarcinoma accounted for most of the CRC, and colonic location was a risk factor for developing CRC.