CEA Level Improves Colon Cancer Staging Prognosis

Assessing carcinoembryonic antigen levels before treatment may improve colon cancer staging

medwireNews: Colon cancer prognosis is improved by inclusion of pretreatment carcinoembryonic Antigen (CEA) level into the TNM staging system, US researchers say on finding the Biomarker to predict poor survival.

The team reviewed medical records of 16,619 patients diagnosed with colonic adenocarcinoma between 2004 and 2005, and stratified patients at each American Joint Committee on Cancer (AJCC) TNM stage for CEA levels considered to be negative or normal (C0) at the time of diagnosis, versus positive or elevated CEA (C1).

After a median of 71 months, multivariate analysis showed that the likelihood of both overall and disease-specific mortality was significantly higher in the 7741 colon cancer patients classified as C1 than their 8878 C0 counterparts with hazard ratios (HRs) of 1.51 and 1.59, respectively.

Patients with a C1 classification had a poorer prognosis than C0 patients for each stage of disease, report Pragatheeshwar Thirunavukarasu, from Roswell Park Cancer Institute in Buffalo, New York, and co-workers.

Moreover, the difference in prognosis between C0 and C1 patients at each AJCC stage was large enough that patients with C1 disease had poorer survival than C0 patients with a more advanced AJCC stage.

For example, the overall mortality of patients with stage IIA C0 disease was lower than that of patients with stage I C1 disease (HR vs stage 1 C0=1.41 and 2.01, respectively), while patients with stage IIIA C0 disease had a better prognosis than those with stage IA C1 or IIA C1 colon cancer (HR=0.89 vs 2.27).

A similar pattern was also found among patients with nondistant nodal metastases, where C1 disease at each stage was associated with equal or poorer survival than C0 colon cancer at a higher nodal stage.

“We recommend routine pretreatment CEA testing as standard of care in colon cancer and use of C stage for multimodality treatment planning and risk stratification in prospective studies and randomized clinical trials”, the team writes in JAMA Surgery.

Ramzi Amri and David Berger, from Massachusetts General Hospital in Boston, USA, note in an accompanying comment that the findings are “in line with earlier recommendations of the American Society of Clinical Oncology and the European Society for Medical Oncology, which call for the incorporation of pretreatment measurement of CEA levels into the standard of care.”

Nevertheless, they caution that an exact threshold for CEA does not exist as the biomarker does not predict outcome in a linear manner and is affected by patient factors such as smoking and liver disease.

“[I]f the C stage is to be incorporated into the [AJCC] staging system, there will need to be clearly defined thresholds with confounder mitigation”, the commentators say. “Once proposed, any cutoff value will need to be extensively validated in large, diverse populations using prospective data before we can conclude that they are universally applicable.”

References

Thirunavukarasu P, Talati C, Munjar S, et al. Effect of incorporation of pretreatment serum carcinoembryonic antigen levels into AJCC staging for colon cancer on 5-year survival. JAMA Surg; Advance online publication 17 June 2015. doi:10.1001/jamasurg.2015.0871

Amri R, Berger DL. Elevation of pretreatment carcinoembryonic antigen level as a prognostic factor for colon cancer. Incorporating a C stage in the AJCC TNM classification. JAMA Surg; Advance online publication 17 June 2015. doi:10.1001/jamasurg.2015.0901

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