P-259 Role of carcinoembryonic antigen as a prognostic marker in colorectal cancer

Abstract

Carcinoembryonic antigen (CEA), is the most widely used tumour marker for colorectal (CRC) for decades. Because of the low diagnostic value, mostly due to the low sensitivity, CEA is not recommended as a screening or diagnostic tool for CRC. Thus, actually the majority of the studies are focused on its possible prognostic utility. Despite the numerous studies, data concerning its utility as a prognostic factor are conflicting. The aim of our study was to evaluate the prognostic value of CEA in our cohort of CRC patients, by defining a correlation with pathological stage and the histopathologic grade of the tumour. This is a single centre retrospective study, conducted at the University Clinic of Gastroenterology, University Hospital Center Mother Theresa, Tirana, Albania. There were included patients over 18 years of age, diagnosed and treated surgically for CRC from January 2014 to December 2017. Serum CEA levels were measured by using radioimmunology assay. Pathological tumour staging was done according to TNM system, AJCC (American Joint Committee on Cancer) 7th edition. Based on CEA levels, CRC patients were divided into two groups: those with normal serum CEA levels (e.g., ≤5 ng/mL), and those with elevated serum CEA levels (>5 ng/mL). Statistical analysis was done using ANOVA and Chi-square test (p-value significance level: 0.05). A total of 95 patients were included in the study, mean age 62.7 ± 11.0 years. 57 (50.8%) man with a mean age 63.58 ± 12.23 and 55 (49.2%) female with a mean age 61.58 ± 10.92. Pathological CEA levels were found in 49/95 (51.6%) patients. As the tumour stage increased, a gradually increase of the proportion of cases with pathological CEA was observed. Pathological CEA levels were found in 25% (2/8) in stage I, 50% (14/28) in stage II, 47.9% (23/48) in stage III and 90.9% (10/11) in stage IV, reaching a statistical significance p=0.024. Mean CEA value measurement showed again a gradual increase with each tumour stage: stage I, 17.96±41.37ng/mL; stage II, 18.37±46.83 ng/mL; stage III 22.05±42.35 ng/mL; and stage IV, 105.13± 170.41 ng/mL (p= 0.003). No relationship was found between histopathology grade and CEA levels (p=0.593). CEA has a prognostic value and it’s useful in CRC staging. Almost all our stage IV CRC patients had pathological CEA values. Lower CEA level suggests an early stage of the tumour, while higher levels indicate advanced stage and probable metastatic disease.