Inflammatory bowel disease (IBD) was found to be associated with increased risk of colorectal cancer (CRC), with smoking identified as a high risk factor for CRC, especially in patients with ulcerative colitis (UC), according to the results of a study published in Medicine.
A team of researchers sought to identify the risks associated with UC and determine a survival curve analysis of the risks. In this retrospective cohort study, 254 patients (mean age, 46.6±16.9 years; mean age at diagnosis, 37.6±15.8 years; 93.3% White; 63.0% women) with UC were evaluated. Inclusion criteria were age ≥15 years and confirmed diagnosis of UC. The most prevalent comorbidities identified were hypertension (24.8%), mood disorders (17.8%), diabetes mellitus (15.0%), and dyslipidemia (12.3%); mesalazine was the most frequently used medication. Extra-intestinal manifestations were reported in 52.4% of patients. At diagnosis, 11.9% of patients were smokers; 5.5% were smokers at their last recorded appointment.
The researchers monitored the patients between March 2016 and October 2017 and found in the univariate regression analysis the presence of CRC correlated with age (odds ratio [OR], 1.058; 95% CI, 1.005 -1.115; P =.03), active smoking (OR, 9.167; 95%, CI, 1.395-60.237; P =.02), and hypertension (OR, 6.407; 95% CI, 1.145-35.865; P =.03) at diagnosis. Similarly, age (OR, 1.059; 95% CI, 1.001-1.121; P =.04) and active smoking (OR, 8.477; 95% CI, 1.350-53.232; P =.02) were each associated with CRC. The risk of CRC was found to be higher in smokers (P =.006) regardless of the extent of UC (P =.05), and smoking was found to be the main risk factor in patients with UC. In addition, age was found to be a higher risk factor when compared with disease duration for IBD-CRC after reporting CRC development at 5 years (1.48%), 10 years (3.17%), and 20 years (4.26%).
Limitations of the study included the lack of information for accumulative inflammatory burden as a risk factor for CRC. The exclusion of 30 patients due to lack of data was also considered as possible selection bias in the study and a population study was suggested.
The study authors concluded, “CRC development in UC patients was relatively low and […] the main risk factor for CRC was the presence of active smoking.” The findings of the study contribute to not only early detection but “also to achieve less exposure to risk factors and a decreased possibility of tumor onset.”
De Campos Silva E, Baima JP, de Barros J, et al. Risk factors for ulcerative colitis-associated colorectal cancer. Medicine. Published online August 7, 2020. doi:10.1097/MD.0000000000021686