A blood test that detects carcinoembryonic antigen (CEA) can improve preoperative risk stratification for patients with stage II colon cancer and guide decisions about adjuvant chemotherapy, say researchers from the Mayo Clinic, Rochester, Minnesota.
Usually, high-risk features used to direct adjuvant therapy for stage II colon cancer are identified postoperatively. But in a retrospective analysis, preoperative elevation in CEA level was identified as a high-risk feature that improved prognostic value of staging predictions in stage II colon cancer over traditional high-risk features.
Giving adjuvant chemotherapy after resection with curative intent appears to “mitigate the increased mortality hazard associated with preoperative CEA elevation in this patient population,” the investigators report.
The study was published in the May issue of the Journal of Gastrointestinal Surgery.
“CEA is an independent prognostic factor for colorectal cancer, meaning that patients with high levels of CEA at diagnosis are at higher risk for recurrence than those with a normal CEA at diagnosis,” senior author Kellie Mathis, MD, told Medscape Medical News.
“We are suggesting that when patients with stage II colon cancer are found to have a high CEA, consideration should be given to administering chemotherapy after recovery from surgery in an effort to improve those patients’ prognosis and survival,” she said.
Every patient with a new diagnosis of colorectal cancer should have this blood test performed.
“Our findings support the guidelines that say every patient with a new diagnosis of colorectal cancer should have this blood test performed,” Dr Mathis told Medscape Medical News.
“The decision to give a patient chemotherapy after surgery is not a light one, and physicians must weigh the risks and benefits,” Dr Mathis added in a news release. “We are currently using the blood test to help make these difficult decisions, and we suggest other physicians do the same.”
For patients newly diagnosed with stage II colon cancer in whom the CEA level is elevated, “physicians should consider chemotherapy in addition to surgery,” said Dr Mathis.
Reached for comment, Seth A. Gross, MD, associate professor of medicine (gastroenterology), NYU Langone Medical Center in New York City, said: “It is true that CEA is a blood test that has been around for many years. Most GI cancer specialists often get a baseline of CEA when we diagnose a new patient with colorectal cancer.
“What is interesting about this article is using CEA as part of the decision process in offering patients chemotherapy after surgery. Oncologists normally follow CEA as a marker, particularly to determine a recurrence of cancer after the level normalizes following therapy,” Dr Gross noted.
CEA Underused in Colon Cancer?
To see whether assessment of pretreatment CEA level can improve risk stratification, Dr Mathis and colleagues mined the National Cancer Database for 2004-2009 for patients with stage II colon adenocarcinoma who underwent resection with curative intent. They developed a “novel” risk stratification system that included both traditional high-risk features (T4 lesion, <12 lymph nodes sampled, and poor differentiation) and elevated CEA level.
Among the 74,945 patients identified, CEA levels had been reported for 40,844 (54.5%) patients; these patients were included in their analyses. “The CEA test is recommended to be done at the time of diagnosis in every patient with colon or rectal cancer. We can assume that some of the patients in the National Cancer Database with a missing data point for CEA actually did have the test performed, but it was not reported. But there were likely many patients in the database who never had the test drawn,” said Dr Mathis.
Patients with an elevated CEA level were more often female and African American, slightly older, and on average had more comorbidities. Pathologic characteristics of tumors from patients with elevated CEA level included increased tumor size, similar tumor grades, a higher rate of positive surgical margins, more T4 lesions, and near equal rates of adequate node sampling.
Rates of adjuvant chemotherapy were similar in patients with normal and and those with elevated CEA levels (23.8% and 25.1%, respectively, P = .003).
According to the researchers, incorporating CEA into the risk model led to reclassification of 6912 patients (16.9%) from average to high risk, a change that could alter treatment, including whether to give chemotherapy.
With surgery alone, 5-year overall survival was lower in patients with elevated CEA level than in those with normal CEA level (66.3% vs 76.0%, P < .001). With adjuvant chemotherapy, 5-year overall survival rose to 85.6% in patients with elevated CEA level and 91.5% in those with a normal level (P < .001).
“Our findings support prior results suggesting that elevated preoperative CEA is an independent risk factor associated with a worse survival and improves prognostic value in stage II colon cancer as demonstrated by the increased mortality hazard to 1.56 from 1.44 (P < .001) as well as the increased concordance probability estimate to 0.634 from 0.612 (SE = 0.005),” write the researchers.
The study had no commercial funding. The authors and Dr Gross have disclosed no relevant financial relationships.
J Gastrointest Surg. 2017;21:770-777. Abstract
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