Abstract: Objective:To explore the risk factors of ulcerative colitisassociated colorectal cancer (UC-CRC).
Methods:The retrospective casecontrol study was conducted. The clinicopathological data of 536 patients with ulcerative colitis (UC) who were admitted to the Henan Tumor Hospital from March 2004 to June 2015 were collected. Observation indicators: (1) followup results: cases with followup, followup time, cases of UC-CRC, age of onset, pathological type of UC-CRC; (2) risk factors analysis affecting occurrence of UC-CRC: gender, age of onset, course of disease, severity of disease, disease classification, extent of lesion, smoking history, family history of colorectal cancer, anemia, hypoproteinemia, body weight loss, extraintestinal manifestations, colonic polyps, backwash ileitis, atypical hyperplasia, anxiety or depression, treatment method and regular endoscopy reexamination. Followup using outpatient examination and telephone interview was performed to detect prognosis of patients up to April 2017. Patients underwent colonoscopy once every 6 months within 3 years after diagnosis and once every 1 year after 3 years. Measurement data with skewed distribution were described as M (range). The univariate analysis was done using the chisquare test and Fisher exact probability. The multivariate analysis was done using the Logistic regression model.
Results:(1) Followup results: of 536 patients, 450 were followed up for 26.0-120.0 months, with a median time of 76.4 months. During the followup, 16 patients were complicated with UC-CRC, including 9 males and 7 females. Age of onset of colorectal cancer was 14-78 years,with an average age of onset of 44 years. Pathological type: highdifferentiated right colon adenocarcinoma was detected in 5 patients, highand moderatedifferentiated left colon adenocarcinoma in 3 patients, left colon signetring cell carcinoma in 2 patients, moderatedifferentiated rectal tubular adenocarcinoma in 3 patients, highdifferentiated rectal papillary adenocarcinoma in 2 patients and malignant lymphoma in 1 patient. (2) Risk factors analysis affecting occurrence of UC-CRC: the results of univariate analysis showed that course of disease, extent of lesion, colonic polyps and atypical hyperplasia were risk factors affecting occurrence of UC-CRC (x²=14.848, 18.885, 10.554, P<0.05). The results of multivariate analysis showed that course of disease >10 years, lesion involving the whole colon, colonic polyps and atypical hyperplasia were independent risk factors affecting occurrence of UC-CRC (OR=12.893, 17.847, 7.326, 19.742, 95% confidence interval: 1.726-74.337, 1.445-89.793, 1.263-43.128, 3.625-96.524, P<0.05).
Conclusion:The course of disease >10 years, lesion involving the whole colon, atypical hyperplasia and colonic polyps are independent risk factors affecting occurrence of UC-CRC.