Background and aims: The role of carcinoembryonic antigen (CEA) in the early detection of recurrence during the postoperative follow-up of colorectal cancer remains unclear. We hypothesize that the tumor with longer lead time of CEA elevation to the definite recurrence may have a better prognosis because of its slower growth rate and closer observation.
Materials and methods: From 1995 to 2003, 4,841 consecutive patients who received curative resection of localized colorectal adenocarcinoma were enrolled from a prospective database. The patients with persisting CEA elevation after operation had been already excluded. Postoperative follow-up, including physical examination, imaging, and CEA test, were performed according to a surveillance program. A CEA >/=5 ng/mL was defined as elevated. The definition of the CEA lead time was the period between CEA elevation and detection of recurrence. All statistical analyses were performed by SPSS package for Windows (Microsoft, Redmond, WA, USA).
Results: The postoperative median follow-up time for the 4,841 patients was 68 months. A total of 999 patients (20.6%) had CEA elevation and recurrence. Among these patients, recurrence was confirmed in 727 patients (72.8%)before, at the same time, or within 3 months of CEA elevation and thus had a short lead time of CEA elevation (SLT group). In 272 patients (27.2%), recurrence was confirmed after more than 3 months of CEA elevation and thus had a longer lead time of CEA elevation (LLT group). The recurrence pattern showed similarities in these two groups. A total of 193 patients (193/999, 19.3%) received a second radical operation, and 806 patients (80.7%) were inoperable. The re-resection rate between the SLT group (146 patients, 20.1%) and the LLT group (47 patients, 17.3%) was not significantly different. The overall survival rate after recurrence showed no difference between these two groups (P = 0.123).
Conclusion: Most cases of recurrence were detected at nearly the same time when the CEA level was elevated. Therefore, a more sensitive test is needed for early detection. The relationship between the lead time of CEA and the clinical outcome was not statistically significant. A more aggressive approach to the patient who has CEA elevation and is highly suspect of recurrence may be needed.