Abstract
Background: For different cancers, different tumor markers are overexpressed. Carcinoembryonic antigen (CEA) levels are raised commonly in adenocarcinoma of colon, breast, and lung. About 80% of primary colorectal cancers (CRCs) show high serum CEA levels. Hence, CEA levels can be used as a prognostic factor - for both metastasis and recurrence - with persistent high levels. Currently, the American Society of Clinical Oncology recommends CEA as tumor marker and prognostic indicator in CRC patients.

Aim and Objectives: The aim of the study was to determine the high level of CEA in CRCs and to study the level of CEA in cases of metastases and recurrence and to determine the sensitivity of CEA value in prognosis of CRCs.

Materials and Methods: It was a prospective observational study. All the patients more than 20 years of age and of both sexes were included in this study who were diagnosed with primary localized CRC, metastatic CRC, or recurrent disease. The study was performed in the Department of General Surgery, R. G. Kar Medical College and Hospital between January 2020 and August 2021.

Results: Total cases were classified according to Duke staging - 10% in Group A, 19% in Group B, 38% in Group C, and 33% in Group D. In Group A and B, about 35% of patients had increased CEA levels, whereas in Group C and D, more than 90% of patients had increased CEA levels with significant P < 0.05. Overall 80% of the patients had elevated CEA levels, so remaining 20% had normal values. In cases of recurrent colorectal carcinoma, >90% of patients had raised CEA levels, and in metastatic disease cases, CEA level was significantly raised in 82% of patients.

Conclusion: In case of colorectal CA, preoperative raised serum CEA level is associated with poor prognosis, as chance of recurrence increased. Along with that increased CEA level is also associated with increased chance of metastatic disease. Hence, serial monitoring of serum CEA level in postoperative period may help to detect any recurrence early, thus reducing chance of mortality and morbidity.

Key words: Carcinoembryonic Antigen; Colorectal Carcinoma; Sensitivity and Specificity