EP267 - Recurrence Risk in Early-Stage (T1) Colorectal Cancer: Preoperative CEA as an Independent Predictor

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Purpose/Background: Colorectal cancer is the third most common malignancy and the fourth leading cause of cancer-related mortality worldwide. Early-stage colorectal cancer (T1) accounts for approximately 40% of cases, generally associated with favorable outcomes. However, recurrence rates following surgical resection in stage T1 colorectal cancer remain reported at 2-10%. This study aims to identify and analyze factors contributing to recurrence in T1 colorectal cancer patients.

Methods/Interventions: This retrospective study included patients diagnosed with T1N0 colorectal cancer who underwent surgical resection at the National Health Insurance Service Ilsan Hospital between January 2002 and December 2018. Relevant clinical data, including demographic information, tumor characteristics, surgical details, and recurrence outcomes, were collected and analyzed.

Results/Outcomes: A total of 110 patients were included in the analysis, with a male predominance (58.2%) and an average age of 65.4 years (±10.2). Tumor locations included the sigmoid colon (46, 41.8%), rectum (35, 31.8%), and ascending colon (17, 15.5%). Surgical procedures performed were anterior resection (47, 42.7%), low anterior resection (37, 33.6%), and right hemicolectomy (19, 17.4%). Of the 39 patients (35.5%) who underwent surgery following endoscopic resection, 17 (43%) exhibited resection margin invasion. Recurrence was observed in five patients, with a median time to recurrence of 16 months (range 4-43 months). Recurrence sites included peritoneal seeding (3 cases) and pulmonary metastasis (2 cases). Patients with recurrence had a higher preoperative mean carcinoembryonic antigen (CEA) level (4.42 ± 2.84 ng/mL) compared to those without recurrence (1.76 ± 1.41 ng/mL), a difference that was statistically significant in univariate analysis (p < 0.001). Multivariate analysis identified elevated preoperative CEA levels as a significant independent risk factor for recurrence (p=0.014, OR 1.618, 95% CI 1.103-2.376), while other factors such as age, gender, endoscopic resection status, margin invasion, lymphovascular invasion, tumor location, tumor size, and histologic differentiation were not significant.

Conclusion/Discussion: Elevated preoperative CEA levels are a significant independent risk factor for recurrence in patients with T1 colorectal cancer following surgical resection. Monitoring CEA levels could be crucial in identifying high-risk patients for closer follow-up and management.