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Abstract
Introduction/Background Loss of estrogen receptor/progesterone receptor (ER/PR) in endometrial cancer (EC) is associated with tumor progression and poor outcomes. Elevated pretreatment cancer antigen 125 (CA 125) level is a risk factor for lymph node metastasis (LNM). We evaluated whether the combination of ER/PR expression and CA 125 level could be used as a biomarker to predict LNM.
Methodology We retrospectively investigated patients with endometrioid EC who underwent complete staging surgery during January 2015-December 2020. We analyzed ER/PR status using immunohistochemical staining, and quantified its expression using the sum of both ER/PR H-scores. Receiver operating characteristic curves were used to identify optimal cut-off values of H-score and CA 125 levels for predicting LNM. A nomogram for predicting LNM was constructed and validated by bootstrap resampling.
Results In 396 patients, the optimal cut-off values of the ER/PR H-score and CA 125 were 407 (AUC 0.645, p=0.001) and 40 U/mL (AUC 0.762, p<0.001), respectively. Multivariate analysis showed that CA 125 ≥ 40 U/mL (OR: 8.03; 95% CI: 3.44–18.77) and ER/PR H-score < 407 (OR: 5.22; 95% CI: 1.87–14.60) were independent predictors. An LNM predictive nomogram was constructed using these two variables. Calibration curves for the probability of LNM showed optimal agreement between the predicted and actual probabilities with a concordance index of 0.807. Our model yielded a negative predictive value and negative likelihood ratio of 98.3% and 0.14, respectively.
Conclusion Our cost-effective prediction model may help gynecological oncologists to guide clinical personalized treatment plan regarding the need of lymphadenectomy. Further confirmatory studies are still required to validate our findings.
Disclosures We report for the first time that a new scoring method for ER/PR status in preoperative curettage in addition to CA125 level may improve the identification of low- and high-risk EC patients for LNM.