Fecal excretion of calprotectin in colorectal cancer - Relationship to tumor characteristics

Background: The aim of this study was to evaluate fecal calprotectin in pat ients treated for colorectal cancer. Furthermore, the changes in fecal calp rotectin concentration from before to after surgery were investigated, Meth ods: In 155 patients with newly diagnosed colorectal cancer, two spot sampl es were taken from the same feces on two consecutive days. Results: Three w ays of evaluating calprotectin excretion were compared, (1st spot 1st stool ; maximum of 1st spot 1st stool and 2nd spot 1st stool; maximum of 1st spot 1st stool and 1st spot 2nd stool) and gave similar results with median fec al calprotectin values 47 mg/l. 52 mg/l and 54 mg/l, respectively. Median c alprotectin concentration did not differ significantly between different tu mor stages, although the levels were slightly lower in Dukes stage A tumor than in the rest of the stages. Neither were there any differences in the c oncentrations related to the localization, size or the histological grading of the carcinoma. As the currently used cut-off level for fecal calprotect in is 10 mg/l, 87% of all patients had elevated fecal calprotectin. Seventy -nine percent of the patients had levels above 15 mg/l and 74% had levels a bove 20 mg/l (1st spot 1st stool). In patients who delivered fecal samples after the operation the calprotectin value fell significantly from a preope rative median value of 45 mg/l to 14 mg/l after the resection. Conclusions: The majority of patients with colorectal cancer have increased fecal conce ntration of calprotectin. One single fecal spot seems to be sufficient fur determination of the calprotectin level. Measurement of fecal calprotectin may possibly become of value as a marker for colorectal cancer, although ca lprotectin, similar to fecal occult blood (FOB) tests, is a non-specific te st for colorectal pathology, also bring elevated in inflammatory bowel dise ases. Further investigation of its specificity is therefore needed.