A Remarkable Case of Elevated Carcinoembryonic Antigen after Surgical Treatment of Rectal Cancer: A Search for its Mysterious Cause

Abstract

Introduction: Measuring carcinoembryonic antigen (CEA) serum levels is frequently used as a biomarker for recurrent disease in follow-up after treatment of colorectal cancer. However, it is also elevated to a significant degree in a number of other malignant and non-malignant conditions. In this case, we present a patient with ongoing elevated CEA levels without a clear cause. Case Presentation: A 57-year-old female patient with adenocarcinoma of the rectum underwent neoadjuvant chemoradiation and a laparoscopic low anterior resection. During follow-up she presented without any clear symptoms but with an ongoing elevation of serum CEA levels, for which she underwent four sequential PET-CT scans within one year without any sign of malignancy. Other causes of elevated CEA levels were investigated and excluded by additional blood tests and imaging studies. Available literature was extensively reviewed but revealed no further possible explanations for the high CEA serum level. Conclusion: The manifestation of an exponential rise of CEA levels following the treatment of colorectal cancer in the absence of abnormalities is a rare presentation and remains a mystery. The cause of the elevated CEA is yet to be elucidated