Prognostic Significance of Preoperative Bowel Obstruction in Stage III Colorectal Cancer

Previous studies have suggested a detrimental prognostic effect of preoperative obstruction proximal to colorectal cancer (CRC). If such a detrimental effect is preserved in each stage of advanced (stage II or III) CRC, we can identify high-risk patients. We enrolled 641 patients with pathologically confirmed advanced CRC (stage II, n = 207; stage III, n = 434) who had undergone curative resection of the primary lesion. The association of preoperative obstruction with clinicopathologic parameters was evaluated. Kaplan-Meier analysis and Cox proportional hazard models were used to estimate the effect of preoperative obstruction on disease-free survival in each stage. Preoperative obstruction was seen in 63 patients (9.8%) (stage II, n = 16; stage III, n = 47). Multivariable analysis showed that preoperative obstruction was significantly associated with preoperative elevation of carcinoembryonic antigen level in patients with colon cancer (odds ratio = 3.59; P < 0.001), while it was correlated with poor differentiation in patients with rectal cancer (odds ratio = 3.99; P = 0.016). Preoperative obstruction was a significant prognostic factor in stage III CRC (P < 0.001), but not in stage II disease. Multivariable prognostic analysis showed that preoperative obstruction was a remnant independent prognostic factor in stage III CRC. This finding was confirmed by separate analyses of colon and rectal cancer. Preoperative obstruction was associated with systemic recurrence (P = 0.003) rather than peritoneal or local recurrence. These findings suggest that preoperative obstruction may predict worse long-term prognosis in patients with stage III CRC and may be a potential clinical marker to identify patients with high-risk stage III CRC.