Objective: To determine if carcinoembryonic antigen (CEA) concentration doubling time (DT) can predict the course of disease and characterize tumor biology.
Design: Retrospective case series of patients who exhibited a distinct increase in circulating CEA during disease recurrence in the routine postoperative follow-up.
Setting: A tertiary general hospital.
Patients: Twenty patients with recurrent gastric carcinoma and 17 patients with recurrent colorectal carcinoma.
Intervention: The CEA DT was determined from semilogarithmic plots of CEA concentration time courses.
Main outcome measurements: The quantitative analyses of the CEA DT as related to various host and tumor characteristics, modes of recurrence, and life expectancy.
Results: The mean CEA DTs for gastric and colorectal carcinomas were 229 days and 86 days, respectively. Although there were no significant differences with regard to patient age, tumor size, gross appearance, and histological differentiation, women had shorter CEA DT than did men. Flow cytometric analysis showed that tumors with a higher proportion of cells in S phase (> or = 15%) had significantly shorter CEA DT than those with a lower S-phase fraction (< 15%). There was a significant correlation between the CEA DT and the length of survival after the initial CEA concentration increase in patients with recurrent gastric and colorectal carcinomas. In the multiple regression analysis of patients who had been treated with curative surgery and chemotherapy, CEA DT proved to be a major independent prognostic factor.
Conclusions: Carcinoembryonic antigen DT predicts life expectancy in patients with adenocarcinoma of the gastrointestinal tract. Differences in survival time are closely associated with variations in the biological aggressiveness of individual tumors.