Prognostic factors for advanced colorectal neoplasia (aCRN) in patients with inflammatory bowel disease (IBD) were outlined in a systematic review and meta-analysis published in Gastroenterology. Overall, 13 risk factors for aCRN were identified, including extensive IBD, low-grade dysplasia, strictures, primary sclerosing cholangitis, post-inflammatory polyps, and family history of colorectal carcinoma (CRC). These data may allow for better risk stratification-based CRC surveillance in patients with IBD.
Investigators searched the PubMed and EMBASE databases for cohort and case-control studies assessing prognostic factors for aCRN in patients with IBD. Eligible studies described 1 or more prognostic factor and provided either an odds ratio (OR) or hazard ratio (HR) to estimate effect size. A random-effects model was used to pool the estimated effects of each prognostic indicator. The Quality in Prognosis Studies (QUIPS) tool was used to assess risk of bias in each study. The quality of evidence for each prognostic indicator was graded as strong, moderate, or weak based on effect size, between-study heterogeneity, and frequency of appearance in selected studies.
Data from 164 studies were included in the analyses. The majority of studies were conducted in Europe (n=83), North America (n=44), or Asia (n=29). More than half of the studies were classified as having “low” risk of bias (n=83), while 32 and 49 were considered to have “moderate” and “high” risk of bias, respectively. Overall, 13 risk factors and 5 protective factors were identified as a result of the analyses. Per pooled estimates from 40 studies, extensive disease was associated with significantly increased likelihood of aCRN compared with left-sided disease (pooled OR, 2.43; 95% CI, 2.01-2.93). The evidence for extensive disease as a risk factor was classified as “strong.”
Moderate-quality evidence supported the prognostic capacity of the following additional risk factors: low-grade dysplasia (pooled OR, 10.85; 95% CI, 5.13-22.97; 8 studies); strictures (7.78; 3.74-16.18; 4 studies); primary sclerosing cholangitis (4.14; 2.85-6.01; 33 studies); post-inflammatory polyps (3.29; 2.41-4.48; 8 studies); family history of CRC (2.62; 1.93-3.57; 15 studies); and a diagnosis of ulcerative colitis vs Crohn disease (1.50; 1.09-2.06; 7 studies). While dysplasia of any kind, colon segment resection, aneuploidy, male sex, and age were also associated with aCRN in univariable analyses, the evidence supporting these associations was weak.
In additional univariable analyses, protective factors included regular colonoscopic surveillance, (OR, 0.39; 95% CI, 0.23-0.66); the use of 5-aminosalicylic acid (5-ASA) drugs (0.53; 0.39-0.72); the use of thiopurines (0.55; 0.37-0.82); and prior or current smoking (0.66; 0.49-0.91). The evidence supporting these findings was of moderate quality. The investigators hypothesized that the anti-inflammatory effect of smoking may have contributed to the lower risk for aCRN observed among smokers. However, this data point should be interpreted with caution, particularly given high between-study heterogeneity. Additional study limitations include the moderate to high risk of bias in several studies and the use of univariable models to identify prognostic factors. Although multivariable estimates were available in some studies, most pooled analyses used univariable estimates. Long-term assessment in a surveillance study is necessary to confirm the prognostic capacity of identified risk factors.
“In this systematic review and meta-analysis…we provided more precise risk estimates of all known prognostic factors for aCRN in IBD patients,” the investigators wrote. These findings may aid in the development of an improved CRC risk stratification model in IBD patients.”
Wijnands AM, de Jong ME, Lutgens MWMD, Hoentjen F, Elias SG, Oldenburg B; on behalf of the Dutch Initiative on Crohn and Colitis (ICC). Prognostic factors for advanced colorectal neoplasia in inflammatory bowel disease: systematic review and meta-analysis. Gastroenterology. Published online December 29, 2020. doi:10.1053/j.gastro.2020.12.036