Reversible Serum Carcinoembriogenic Antigen (CEA) Elevation Due to Orlistat Use: A Case Report

Carcinoembriogenic antigen (CEA) is a serum marker commonly used as a clinical tool in the follow-up of patients with several types of tumor, particularly colorectal carcinoma. An elevation in CEA levels can precede clinical evidence of recurrence, but these levels can also increase in patients with nonmalignant pathologies. Nevertheless, an elevation in CEA levels is always associated with the introduction of extensive work-ups and typically generates significant patient anxiety. Orlistat is a medication commonly used as an adjunctive weight-control measure due to its ability to decrease the absorption of dietary triglycerides. Its predominant side-effects are related to its activity in the gastrointestinal tract. We report the case of a patient who developed a documented, reversible elevation in CEA with the use of this medication. The use of orlistat should be considered in the differential diagnosis of patients presenting unexplained elevations of CEA.