P-301 Pre-surgical carcinoembryonic antigen as a recurrence biomarker in stage III colon cancer treated with adjuvant chemotherapy in a Latin American center

Abstract

Colorectal cancer represents the third most incident malignant neoplasm in the world and the second in terms of mortality. In Peru, colon cancer is positioned as the fifth malignant neoplasm in terms of incidence and the sixth, in terms of mortality(1). Surgery continues to be the curative therapy for this pathology, however, the risk of disease recurrence is still a subject of study, as well its association with risk factors, such as the degree of tumor invasion (T) and lymph node involvement (N)(2). Likewise, the role of other factors has been shown to have prognostic relevance in colon cancer patients(3,4). The main objective of this research was to determine if the preoperative carcinoembryonic antigen (CEA) level is a prognostic biomarker of recurrence and survival in patients with stage III colon cancer. A cross-sectional descriptive study was carried out, between the years 2013 and 2018, 1987 patients with colon cancer were analyzed, of which 162 patients were stage III and received adjuvant treatment with chemotherapy based on fluoropyrimidines and who complied with the inclusion criteria. The preoperative CEA level was studied (cutoff point 5); secondarily, the following clinicopathological characteristics were evaluated: age ( 45 years), albumin level ( 35 g/L), location of the primary colon (right colon vs. left colon), lymphovascular invasion (present, absent), perineural invasion (present, absent), histological grade (1, 2 or 3). The mean age was 63.7 years, 63 patients were women (38.9%), 99 patients were men (61.1%). Univariate analysis showed that the level of CEA > 5 is statistically significant (p=0.005) for recurrence. Likewise, the multivariate analysis maintained the finding of a CEA level > 5 (HR 2.71, 95%IC [1.25-5.85], p=0.011) as a prognostic factor for recurrence. Median follow-up for disease-free survival (DFS) was 31.36 months. Median DFS was not reached in either group. The DFS at 3 years in the group with CEA 5. The evaluation of the other clinicopathological characteristics were not significant. As well, it was possible to determine that the majority of recurrence cases, in the group of patients with CEA > 5, were in the first two years with a total of 18 of 21 events (85.71%). In patients with stage III colon cancer who have received adjuvant therapy, a CEA level greater than 5 has a negative impact on disease-free survival. Likewise, the greatest risk for presenting recurrence, in patients with elevated CEA, is seen in the first 2 years.