ROSH Gastrointestinal Practice Exam

In a patient suspected of rectal neoplasia with positive fecal occult blood test, which serum test is most appropriate for initial evaluation?

1. Alpha fetoprotein (AFP)

2. Cancer antigen 127- (CA-125)

3. Cancer antigen 15-3 (CA-15-3)

4. Carcinoembryonic antigen (CEA)

The correct answer is: Carcinoembryonic antigen (CEA)

In patients with suspected rectal neoplasia, particularly when a fecal occult blood test result is positive, the most appropriate serum test for initial evaluation is carcinoembryonic antigen (CEA). CEA is a tumor marker that is often elevated in various types of cancers, including colorectal cancer. Its levels can be monitored to assist in diagnosing cancer, assessing prognosis, and following the response to treatment. In the context of rectal neoplasia, the elevation of CEA can indicate malignancy, making it a useful tool in the early evaluation of patients with such findings. Additionally, CEA serves as a helpful biomarker to track disease progression or recurrence after treatment. While other markers such as alpha fetoprotein (AFP), cancer antigen 127 (CA-125), and cancer antigen 15-3 (CA-15-3) are useful in specific types of cancers, they are not routinely used for colorectal or rectal malignancies. For example, AFP is primarily associated with liver cancers and germ cell tumors, while CA-125 is typically associated with ovarian cancer, and CA-15-3 is linked to breast cancer. For this reason, CEA is the most relevant choice in the context of suspected rectal neoplasia