Background/aims: We hypothesize that a subset of node-negative colorectal cancer patients exists that is at high risk for recurrence after curative surgery. Preoperative serum levels of sialyl Lewisa (CA19-9), sialyl Lewisx (SLX), sialyl Tn (STN), and carcinoembryonic (CEA) antigens were analyzed for their value in predicting for such a group.
Methodology: One-hundred-forty-five patients with node-negative, T1-4, M0 colorectal cancers were divided into groups of low or high serum antigen levels. Disease-free interval served as the endpoint in evaluating the prognostic strength of each variable.
Results: Twenty-seven patients (18.6%) were included in the high group for CA19-9 antigen, 11 (7.6%) for SLX, 13 (9.0%) for STN, and 51 (35.2%) for CEA. The median follow-up was 62.1 months. As compared to those with low levels, patients with elevated CA19-9 had a shorter disease-free interval (P = 0.0026). No significant difference in disease-free interval was noted between low and high groups of SLX, STN, and CEA antigens. Cox regression analysis identified elevated serum CA19-9 level as a predictor for decreased disease-free interval, independent of T-stage or tumor location.
Conclusions: Elevated preoperative serum levels of CA19-9 may serve as a useful marker in identifying patients with node-negative colorectal cancers at high risk for recurrence after surgery.