For patients with stage II or III colorectal cancer, CEA testing after surgery is recommended every three months, for at least three years after diagnosis. Along with other tests, CEA tests are one way doctors can find out whether the cancer has spread or returned. Cancer that has spread or returned can be treated successfully for many patients. For more information about the recommended tests after treatment for colorectal cancer, read What to Know: ASCO's Guideline on Follow-Up Care for Colorectal Cancer [1].

For patients with metastatic pancreatic cancer (cancer that has spread outside the pancreas to other parts of the body), CA 19-9 may be measured at the beginning of treatment and every one to three months during treatment. Other tests may be used along with the CA 19-9 test to decide the best treatment.

The other tumor markers in this guide require further research before they can be recommended. It is important to talk with you doctor about what tumor marker tests are most appropriate for your situation. Patients are also encouraged to talk with their doctor about enrolling in clinical trials of tumor marker tests.