Impact of preoperative CEA levels on the prediction of lymphnode (LN) metastasis

Abstract

20070 Background: Although CEA is the most commonly used tumor marker for colorectal carcinoma (CRC) and it may correlate with poorer prognosis, data are insufficient to support its use to determine adjuvant therapy. Monitoring preoperative CEA might be useful if it would assist in staging and treatment planning. Methods: This study was a pooled data analysis of 1791 CRC patients (pts) collected prospectively from 25 hospitals participating in the MCSGO. The purpose of this study was to investigate the impact of preoperative CEA on the prediction of the number of LN metastasis (#LN). Data of 1328 pts were completed with preoperative CEA and clinicopathological (CP) data (number of dissected LN, #LN, tumor size, distant metastasis, macroscopic type, depth of invasion, histological type, and lymphatic and vessel invasion). Data of 582 pts with the number of dissected LN 12 were analyzed in this study. #LN was categorized in 5 levels (0, 1, 2, 3, and ≥4), and relationship between #LN and CEA was first investigated via a multivariate analysis based on adjusting for the other CP factors. Discrete logistic regression analysis was used, in which a random effect was incorporated to adjust some bias between hospitals. The linear effects for the factors were evaluated via the regression model. The multivariate adaptive regression spline (MARS), the most powerful tool in the statistical prediction, was employed for the prediction of #LN. Results: The effect of the CEA adjusted by the other CP factors had a positive trend with two-sided P-value of 0.0394 for #LN. The adjusted R-squared measure (R2*) by the MARS fitting, a prediction performance index of #LN, was 0.369, and that averaged based on Bootstrap sampling (Bagging method) was R2* = 0.405. The relative importance of each factor in the prediction of #LN estimated by the decrease rate of R2* on masking each factor is shown in the Table . The relative importance of CEA in the prediction of LN# was ranked second next to lymphatic invasion. Conclusions: Preoperative CEA has a significant impact on the prediction of #LN. [Table: see text] No significant financial relationships to disclose.