L1CAM in Early-Stage Type I Endometrial Cancer: Results of a Large Multicenter Evaluation

Despite the excellent prognosis of Fdration Internationale de Gyncologie et dObsttrique (FIGO) stage I, type I endometrial cancers, a substantial number of patients experience recurrence and die from this disease. We analyzed the value of immunohistochemical L1CAM determination to predict clinical outcome. We conducted a retrospective multicenter cohort study to determine expression of L1CAM by immunohistochemistry in 1021 endometrial cancer specimens. The KaplanMeier method and Cox proportional hazard model were applied for survival and multivariable analyses. A machine-learning approach was used to validate variables for predicting recurrence and death. Of 1021 included cancers, 17.7% were rated L1CAM-positive. Of these L1CAM-positive cancers, 51.4% recurred during follow-up compared with 2.9% L1CAM-negative cancers. Patients bearing L1CAM-positive cancers had poorer disease-free and overall survival (two-sided Log-rank P < .001). Multivariable analyses revealed an increase in the likelihood of recurrence (hazard ratio [HR] 16.33; 95% confidence interval [CI] 10.55 to 25.28) and death (HR 15.01; 95% CI 9.28 to 24.26). In the L1CAM-negative cancers FIGO stage I subdivision, grading and risk assessment were irrelevant for predicting disease-free and overall survival. The prognostic relevance of these parameters was related strictly to L1CAM positivity. A classification and regression decision tree (CRT)identified L1CAM as the best variable for predicting recurrence (sensitivity 0.74; specificity 0.91) and death (sensitivity 0.77; specificity 0.89). To our knowledge, L1CAM has been shown to be the best-ever published prognostic factor in FIGO stage I, type I endometrial cancers and shows clear superiority over the standardly used multifactor risk score. L1CAM expression in type I cancers indicates the need for adjuvant treatment. This adhesion molecule might serve as a treatment target for the fully humanized anti-L1CAM antibody currently under development for clinical use.