As C-reactive protein levels and erythrocyte sedimentation rates go up in patients with inflammatory bowel disease, the risk of colorectal cancer goes up, too, a finding that suggests a role for both as markers of colon cancer risk, Boston investigators reported in a prospective study published online Jan. 6 in Clinical Gastroenterology and Hepatology.
The team divided 3,145 IBD patients into quartiles based on median C-reactive protein (CRP) levels, and 4,008 others into quartiles based on median erythrocyte sedimentation rates (ESR), then followed them for a median of 6 years.
On multivariate analysis, there was a significant increase in the risk of colorectal cancer (CRC) across quartiles of CRP elevation (P for trend = .017). Higher median ESR was also independently associated with higher risk of CRC across quartiles (P for trend = .007) (Clin. Gastroenterol. Hepatol. 2014 Jan. 6 [doi: 10.1016/j.cgh.2013.12.030]).
"This association adds another clinical variable to help stratify patients into risk categories. There is an important need to identify high-risk subgroups that may benefit from continued intensive surveillance strategies while allowing for less frequent colonoscopies in patients at low risk of CRC. We believe that our findings ... suggest that an individual patient’s severity of inflammation may be helpful in further personalizing surveillance recommendations," and might even help monitor other outcomes, including treatment response, said the authors, led by Dr. Ashwin Ananthakrishnan, a gastroenterologist at Massachusetts General Hospital, Boston.
After adjustment for age, sex, race, IBD type, and other factors, the patients in the highest CRP quartile had more than double the risk of colorectal cancer compared with those in the lowest quartile (OR 2.72, 95% CI 0.95-7.76). The strength of association was similar in men and women, and in Crohn’s disease and ulcerative colitis.
Similarly, patients in the highest ESR quartile had double the risk compared with those in the lowest (OR 2.06, 95% CI 1.14-3.74). The correlation was strongest in ulcerative colitis patients and men.
The median CRP values in each of the quartiles were 0.8, 2.7, 7.5, and 32.8 mg/L. In the ESR group, the median quartile values were 7, 14, 25, and 50 mm/hr.
Overall, 33 patients in the CRP cohort and 102 patients in the ESR cohort developed colorectal cancer at a median age of 55 years. The median number of CRP measurements was three, and median number of ESR measurements six. More than half the subjects were women, most were white, and ulcerative colitis was slightly more common than was Crohn’s disease.
Adjusting for number of colonoscopies, intensity of health care utilization, use of corticosteroids, and other factors did not change results for either the CRP or ESR cohorts.
The National Institutes of Health funded the work. The investigators have no disclosures.