OBJECTIVE: Colorectal cancer (CRC) is the third most common cancer type in the world. Carcinoembryonic antigen (CEA) is widely used as a marker for CRCs. Interleukin-8 (IL-8) is a pro-inflammatory cytokine noticeably up-regulated in CRCs. Research have been conducted in different populations to investigate the CEA and IL-8 levels in CRCs and to elucidate their correlation with clinical findings. However, data on Sri Lankan CRC patients are sparse; none reports the CEA or IL-8 levels or their correlations with clinical findings. The objective of this study was to compare the CEA and IL-8 levels in a cohort of CRC patients.

PATIENTS AND METHODS: Blood samples from forty patients with CRCs and thirty-five healthy volunteers were obtained after informed consent. Their clinical findings and CEA values were recorded. The concentrations of IL-8 were measured using enzyme-linked immunosorbent assay (ELISA). The mean values of IL-8 levels in patients and the control group were compared and the data were analysed to evaluate if there is a correlation between CEA and IL8 levels.

RESULTS: At the time of diagnosis, most of the tumors were moderately differentiated (83%) and the average tumor length was 4.4 cm. The tumor location was mostly left-sided (88.7%). Mean CEA level was 21.3 ng/dl at the diagnosis. Mean [IL-8] in patients was 38.16 pg/ml and was higher than that of controls (33.67 pg/ml). However, the difference was not statistically significant (p > 0.05). Additionaly, a strong positive correlation between [CEA] and [IL8] was not observed (r=0.19).

CONCLUSIONS: This study shows that most of the CRCs are diagnosed at moderately differentiated stage with high CEA values. The results of this study are in favor of using CEA as a diagnostic marker. It provided no evidence of a correlation between high CEA and IL-8. Even though not significantly different from that of controls, elevated IL-8 could be a potential marker for CRCs which needs further validation by higher sample numbers.