Elevated C-reactive protein levels are not a feature of uncomplicated radiation-induced bowel injury

An elevated C-reactive protein (CRP) is a valuable marker of disease activity in Crohn's disease and predicts colectomy in ulcerative colitis. It is sometimes elevated in patients with chronic gastrointestinal symptoms following pelvic radiotherapy. Its significance in this context has not been evaluated. The aim of this study was to investigate the significance of elevated CRP in patients with new gastrointestinal symptoms starting after pelvic radiotherapy. Patients at presentation to a specialist clinic had their CRP measured. The diagnoses reached were grouped into categories and correlated with the level of the CRP using logistic regression analysis. Between 2001 and 2004, 159 patients [91 women (median age 61 years), 68 men (median age 69.5 years)] with new gastrointestinal symptoms after pelvic radiotherapy (median 3 years previously) had their CRP checked. In total, 132 (83%) patients had a normal CRP (<10 mg/L). Twenty-seven had an elevated CRP (median 18, range 10-79 mg/L). Eight categories of diagnosis were recorded for patients, including advanced neoplasia (n = 18), small bowel disease (n = 43), large bowel disease (n = 42), ano-rectal disease (n = 72), infection (n = 5), pancreatic insufficiency (n = 5), drugs (n = 7) and normal/other (n = 45). On univariate analysis, presence of advanced neoplasia [P = 0.01 (OR 3.85, 95% CI 1.34-11.1)] and the presence of pancreatic insufficiency [P = 0.026 (OR 8.13, 95% CI 1.29-51.23)] were associated with an elevated CRP. An elevated CRP level is not a prominent feature of uncomplicated chronic radiation-induced toxicity in the gastrointestinal tract. If present in patients with suspected radiation-induced damage, other causes must be sought.