Preoperative interleukin-6 in colorectal cancer patients: correlation with carcinoembryonic antigen, tumour stage and outcome

ABSTRACT

The significance of preoperative serum inter-leukin-6 [IL-6] level in the progression of colorectal cancer has not been fully elucidated. Our aim was to investigate its role and identify its prognostic significance. Forty three consecutive patients, who underwent radical resections for colorectal cancer lesions in a period of 1.5 years from Aug. 2004 till Feb. 2006 were recruited in this study. Blood samples were obtained before surgery to determine the serum concentration of IL-6 and carcinoembryonic antigen [CEA]. Serum concentrations of human IL-6 were determined by enzyme-linked immunosor-bent assay [ELIZA] and CEA was measured by immunometric method. The relationships between their elevations and both the clincopathological factors and prognosis of patients were investigated. Serum samples [for IL-6 assay only] from 25 sex- and age-matched normal healthy individuals were used as controls. The mean serum IL-6 concentration [9.57 +/- 7 pg/mL, range 2.4-45 pg/mL] was significantly higher than that in normal individuals [mean value 3.52 pg/mL, range 0.45-9.96 pg/mL, p<.001]. Elevated serum CEA [>5.0 ng/mL] was present in 44.2% of patients, while serum IL-6 levels in CRC patients were more frequently elevated [69.8% of patients, p=.001]. Linear regression analysis showed a significant association between serum values of both IL-6 and CEA [r=.773; r[2]=.597; p=.001]. The mean IL-6 serum concentration in CRC patients with stage III was 13.3 +/- 8.47 pg/mL while the mean level in patients with stage I and II was 6.3 +/- 3 pg/mL [p=.001]. Patients with an IL-6 serum concentration of more than 9.5 pg/ml had a significantly shorter 2-year survival [55%] than patients with an IL-6 serum concentration of 9.5 pg/ml or less [93%], [p=001]. IL-6 is potentially a better marker for advanced colorectal carcinoma than CEA. High preoperative levels were associated with high CEA, advanced tumor stage and poor outcome. IL-6 may have a role as an indicator of metastases that appear after resection of the primary colon cancer. This may help to identify high risk patients more likely to benefit from adjuvant therapy