The predictive value of CA-125 for radiologic evidence of metastatic disease in type 2 endometrial cancers.

Abstract

e17610 Background: Type 2 endometrial cancers encompass histologic variants that are more aggressive and have a higher incidence of extrauterine disease at the time of presentation than their type 1 counterparts. For high grade endometrial carcinomas, current National Comprehensive Cancer Network (NCCN) guidelines propose the "consideration of chest, abdomen and pelvis CT to evaluate for metastatic disease." We sought to investigate the predictive value of serum CA-125 for radiographic evidence of metastatic disease in patients with type 2 endometrial cancers. Methods: An IRB-approved, retrospective study investigating patients diagnosed with endometrial cancers between 2000-2020 at an urban, multi-site health system was conducted. Only patients with type 2 endometrial cancers and both pre-operative computed tomography scans of the chest, abdomen, and pelvis (CT CAP) and serum CA-125 results were included. A Youden’s index was used to calculate the optimal CA-125 cutoff. The sensitivity and specificity of CA-125 in predicting radiographic evidence of extrauterine disease was then calculated using this pre-determined CA-125 cutoff. Results: In total, 2,227 patients diagnosed with endometrial cancer (types 1 and 2) between 2000-2020 were identified. 1,932 cases were excluded due to low grade disease and/or the absence of pre-operative imaging and CA-125 results. Ultimately, 295 cases were included in analyses. A receiver operating characteristic (ROC) curve was used to generate Youden’s index which established the optimal CA-125 cutoff as 68 U/mL (P=0.0005). Using this cutoff, the specificity and sensitivity were determined to be 92.45% and 63.86%, respectively. The positive predictive value was 76.81% and the negative predictive value was 86.73%. Conclusions: According to current NCCN guidelines, pre-operative imaging and CA-125 should be considered if extrauterine disease is suspected in the setting of endometrial cancer. Although the role of serum CA-125 in monitoring clinical response is well documented, the utility of this test in stratifying patients who should undergo further radiologic evaluation is uncertain. Our results suggest that a CA-125 cutoff of > 68 U/mL is predictive of radiographic evidence of metastatic disease and, thus, can be used to determine which patients should receive pre-operative CT CAP.