Preoperative Cancer Antigen 125 Level as Predictor for Complete Cytoreduction in Ovarian Cancer: A Prospective Cohort Study and Systematic Review

SIMPLE SUMMARY: Standard treatment of advanced stage epithelial ovarian cancer consists of cytoreductive surgery (CRS) and chemotherapy. Prolonged progression free and overall survival is correlated with the amount of residual tumor after CRS. However, cytoreductive surgery is an extensive procedure with a considerable risk of postoperative complications. Therefore, it would be valuable to have parameters that can predict the surgical outcome. In this study, we evaluated the value of the blood tumor marker CA-125 to predict complete CRS to no residual tumor. The results of our study suggest that CA-125 levels ≤35 kU/L significantly predict the surgical outcome in patients who underwent interval cytoreductive surgery, but this parameter cannot be used as an independent predictor. This contrasts with the outcome of our systematic review with mainly retrospective data, which found CA-125 as an independent predictive variable. ABSTRACT: Background: The tumor marker ‘cancer antigen 125’ (CA-125) plays a role in the management of women with advanced stage ovarian cancer. This study aims to describe the predictive value of pre-treatment CA-125 level and the reduction after neoadjuvant chemotherapy (NACT) on surgical outcome. Methods: A systematic review and a prospective clinical study were performed. Multiple databases were searched from database inception to April 2022. The clinical study is part of a randomized controlled trial named “PlaComOv-study”. A regression analysis was performed to demonstrate correlations between preoperative CA-125 levels, CA-125 reduction after NACT, and surgical outcome. Results: Fourteen relevant articles were analyzed of which eleven reported that lower preoperative CA-125 levels were associated with a higher probability of complete cytoreduction. In the clinical study, 326 patients with FIGO stage IIIB-IV ovarian cancer who underwent CRS were enrolled from 2018 to 2020. Patients who underwent interval CRS with preoperative CA-125 levels ≤35 kU/L had higher odds of achieving complete CRS than patients with CA-125 level >35 kU/L (85% vs. 67%, OR 2.79, 95%CI 1.44–5.41, p = 0.002). In multivariable analysis with presence of ascites and peritoneal carcinomatosis, normalized preoperative CA-125 did not appear as a significant predictor for complete CRS. Conclusions: In literature, preoperative CA-125 levels ≤35 kU/L were associated with a significant higher percentage of complete CRS in univariable analysis. According to our cohort study, preoperative CA-125 level ≤35 kU/L cannot independently predict surgical outcome either for primary or interval CRS.