Objective: The aim of the study is to re-validate CRS as a prognostic factor for ovarian cancer patients who received front-line maintenance therapy or intra-operative chemotherapy. Methods: The retrospective analysis was performed with the medical records from tubo-ovarian high grade serous carcinoma patients who received neoadjuvant chemotherapy followed by interval debulking surgery between January 2007 to December 2021 at five tertiary medical institutions in South Korea. Progression-free survival (PFS) and overall survival (OS) were obtained using Kaplan-Meier analysis; the aforementioned was used to evaluate the effect of BRCA mutation, Poly-ADP Ribose Polymerase (PARP) inhibitor, bevacizumab, hyperthermic intraperitoneal chemotherapy (HIPEC), and CRS. Results: A total 549 patients were analyzed. BRCA 1/2 mutations were detected in 178(32.4%) patients and 117(21.3%) patients were treated with PARP inhibitors, and 57(10.4%) patients were treated with bevacizumab as a front-line maintenance therapy. CRS3 in patients with BRCA wildtype was associated with improved PFS (25.9 vs 15.2 months, p<0.001) compared to CRS 1 or 2. However, there is no significant PFS prolongation of CRS3 in patients with BRCA mutation compared to CRS 1 or 2 (22.0 vs 19.3 months, p=0.17). In addition, CRS3 in PARP inhibitors-naive patients improved PFS significantly longer than CRS 1 or 2 (24.7 vs 15.5 months, p<0.001), whereas CRS3 in patients with PARP inhibitors as a front-line maintenance therapy were not significantly associated with prolongation of PFS (24.3 vs 22.4, p=0.85). Similarly, in opposition to bevacizumab-naïve patients, no statistically significant PFS prolongation of CRS3 was revealed compared to CRS1 or 2 in patients with front-line bevacizumab maintenance therapy (27.5 vs 17.5 months, p=0.202). Conclusion: Contrary to previous research, the CRS system may not be a prognostic factor in patients affected by BRCA mutation or treated with front-line maintenance therapy such as PARP inhibitors or bevacizumab.