Which tumor marker is used to monitor colon cancer?

Which tumor marker is used to monitor colon cancer?

• A. CA-125
• B. CEA
• C. AFP
• D. PSA

Answer: (B)

For colon cancer, monitoring disease activity over time is achieved with a tumor marker that reflects tumor burden and response to treatment. Carcinoembryonic antigen (CEA) is the marker used for this purpose. In patients with known colon cancer, serial CEA measurements help track how well therapy is working and can signal recurrence when levels rise. A falling CEA during treatment suggests tumor response, while increasing levels may indicate progression or relapse. However, CEA is not perfect for screening or diagnosis because it can be elevated in other conditions (smoking, inflammatory states, and non-colorectal malignancies), and some cancers do not produce much CEA. So, while CEA is the best-established marker to monitor colon cancer, it should be interpreted in the context of imaging and clinical findings. Other listed markers correspond to different cancers (CA-125 with ovarian cancer, AFP with liver and some germ cell tumors, PSA with prostate cancer).

For colon cancer, monitoring disease activity over time is achieved with a tumor marker that reflects tumor burden and response to treatment. Carcinoembryonic antigen (CEA) is the marker used for this purpose. In patients with known colon cancer, serial CEA measurements help track how well therapy is working and can signal recurrence when levels rise. A falling CEA during treatment suggests tumor response, while increasing levels may indicate progression or relapse. However, CEA is not perfect for screening or diagnosis because it can be elevated in other conditions (smoking, inflammatory states, and non-colorectal malignancies), and some cancers do not produce much CEA. So, while CEA is the best-established marker to monitor colon cancer, it should be interpreted in the context of imaging and clinical findings. Other listed markers correspond to different cancers (CA-125 with ovarian cancer, AFP with liver and some germ cell tumors, PSA with prostate cancer).