Underused Blood Test Helps Alter Treatment Strategy for Colon Cancer

A routinely available blood test can help improve risk stratification and guide additional therapy for stage II colon cancer.


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Adjuvant therapy is often guided by high-risk features in stage II colon cancer. Currently, high-risk features are often identified postoperatively, which limits preoperative risk stratification.

Kellie Mathis, MD, colon and rectal surgeon, Mayo Clinic (Rochester, MN), and colleagues conducted a study to determine whether a blood test that measures carcinoembryonic antigen (CEA)—which is highly expressed in colon cancer—could help improve preoperative risk stratification for stage II colon cancer. Using data from the National Cancer Database, researchers sampled data from 40,844 patients to assess benefit from a CEA-measuring blood test for risk stratification and potential treatment alterations. Results of the study were published in the Journal of Gastrointestinal Surgery (May 2017;21[5]:770-777).

Results of the assessment showed that had CEA test results been known prior to surgery, the classification of approximately 17% of patients with stage II colon cancer would have been upgraded from average to high-risk. Furthermore, this upgrade would have altered the available treatment options, including whether to use chemotherapy after surgery.

“There is no good reason for a physician to omit this blood test, and more work needs to be done to ensure that all patients receive it,” Dr Mathis said in a press release (June 21, 2017).

Authors of the study noted that patients who do receive the CEA test often receive it after surgery to monitor their cancer’s development. However, earlier consideration of CEA level may be warranted.

Additionally, patients with stage II disease who had surgery without adjuvant chemotherapy experienced better 5-year survival rates if they did not have elevated CEA levels (76%) than if they had elevated CEA levels (66%). Those patients with elevated CEA levels fared better if they received adjuvant chemotherapy than if they underwent surgery alone.

“If a patient with a new diagnosis of stage 2 colon cancer has an elevated carcinoembryonic antigen level, physicians should consider chemotherapy in addition to surgery,” concluded Dr Mathis.—Zachary Bessette