583P - Pre-op CEA influences interpretation of CEA dynamics for surveillance of recurrent colorectal cancer

Date 01 October 2012
Event ESMO Congress 2012
Session Poster presentation III
Topics Colon Cancer
Rectal Cancer
Presenter Dawn Chong
Authors D. Chong1, C. Phuan2, C. Tan2, L. Lee2, T. Aung2, C. Chua3, D.W.M. Tai3, I.B. Tan3
  • 1National Cancer Centre, 169610 - Singapore/SG
  • 2Medical Oncology, National Cancer Centre, 169610 - Singapore/SG
  • 3Dept. Medical Oncology, National Cancer Centre, 169610 - Singapore/SG

Abstract

Background

Serial serum carcinoembryonic antigen (CEA) assays are routinely performed following curative resection of colorectal cancer. The interpretation of post-op CEA dynamics in relation to pre-operative CEA values remains unclear. The aim of our study was to determine the value of pre-op CEA levels in interpreting subsequent rises in CEA for detection of recurrent disease.

Methods

We identified 699 patients who developed recurrent disease following curative resection of colorectal cancer. Patient's demographics, clinical and histopathologic characteristics, time to recurrence were evaluated in relation to pre-op CEA levels and CEA dynamics. Median time to recurrence was 20 months (95%CI: 27.3-35.0).

Results

Prior to curative surgery, 49.5% of patients had a Pre-op CEA > 5 Ug/L (primary tumor is a “secretor”) whilst 50.5% did not have elevated pre-op CEA (“non-secretor”). The pre-op CEA value is prognostic (continuous variable, p < 0.01). During follow-up, all non-secretors and 58% of secretors achieved a trough CEA < 5 Ug/L. Achieving a trough CEA <5 Ug/L was associated with longer time to recurrence (HR 0.52, 95%CI: 0.36-0.73, p < 0.01). A new rise in CEA to > 5 Ug/L prior to relapse was observed in 51% of all patients. This new rise was more likely to be observed among patients whose initial primary was secretory (p < 0.01). The median time from new rise in CEA to clinical relapse was 2.4 months. This was not different between initial secretors and non-secretors. At clinical relapse, 82% of initial secretors vs 47% of initial non-secretors had elevated CEA (p < 0.01).

Conclusions

Pre-operative CEA levels prior to initial surgery influence CEA dynamics post curative resection in patients with recurrent colorectal cancer. Among secretors, fall to baseline CEA is associated with longer time to recurrence. Among all patients, a new rise in CEA is more likely to occur in patients whose initial primary is secretory. Once this new rise occurs, median time to recurrence is 2.4 months and this duration is not dependent on initial secretory status.

Disclosure

All authors have declared no conflicts of interest.