Nadir CA-125 serum levels during neoadjuvant chemotherapy and no residual tumor at interval debulking surgery predict prognosis in advanced stage ovarian cancer

BACKGROUND: Recent phase III randomized trials have suggested that neoadjuvant chemotherapy followed by interval debulking surgery (NACT-IDS) is a treatment option for patients with advanced epithelial ovarian cancer. This study aimed to use CA-125 and computed tomography (CT) scanning to generate a simple and clinically applicable model of predicting complete cytoreduction by interval debulking surgery (IDS) and the overall survival in patients who receive taxane/platinum-based chemotherapy as neoadjuvant chemotherapy (NACT). METHODS: Patients with stage IIIc or IV epithelial ovarian cancer who underwent taxane/platinum-based NACT followed by IDS in Gunma Prefectural Cancer Center, Takasaki General Medical Center, and Gunma University from April 2009 to March 2015 were included. Patients underwent a CT scan to confirm confirm tumors unresectable by standard surgery before NACT. CA-125 levels were measured pre-NACT, after each cycle of NACT, and before IDS. CT was also performed before IDS to evaluate tumor metastasis. Data were collected retrospectively and analyzed to determine the predictive factors of complete resection and overall survival. RESULTS: Among 63 patients who received NACT-IDS, 43 and 20 patients had stages IIIc and IV epithelial ovarian cancer at diagnosis, respectively. CT predictors of residual tumors after IDS such as extra-ovarian implants (P = 0.009) and omental cakes (P = 0.038) were not present. Univariate analysis revealed that the independent factors for overall survival were no residual tumor by IDS (P = 0.0016) and CA125 ≤ 20 U/ml before IDS (P = 0.0011). CONCLUSIONS: Although this study had a small sample size, NACT-IDS used to completely remove macroscopic disease which significantly improved the prognosis of patients with preoperative CA-125 ≤ 20 U/ml. Results from this study provide useful information for future studies on the management of patients with advanced epithelial ovarian cancer.