EP237/#590 Role of secondary cytoreductive surgery and bevacizumab in platinum-sensitive recurrent ovarian clear cell carcinoma

Objectives Ovarian clear cell carcinoma (OCCC) is associated with a higher recurrence rate and tends to develop chemoresistance. Currently, optimal management of recurrent OCCC has not yet been established. Thus, we aimed to investigate survival according to the treatment methods in platinum-sensitive relapsed OCCC. Methods From five institutions, we identified OCCC patients with platinum-sensitive recurrence who received secondary treatment between 2007 and 2021. Patient characteristics and survival outcomes were compared according to the use of bevacizumab (BEV) during second-line chemotherapy and secondary cytoreductive surgery (CRS). Results In total, 138 patients were included. The BEV group (n=36) showed improved progression-free survival (PFS; median, 15.4 vs. 7.5 months; P=0.042) and overall survival (OS; P=0.043) compared to the non-BEV group (n=102). In multivariate analyses, BEV was identified as an independent prognostic factor for PFS (aHR, 0.571; 95% CI, 0.354–0.921; P=0.022) and OS (aHR, 0.435; 95%CI, 0.195–0.970; P=0.042). The secondary CRS group (n=42) had multi-site metastasis (P<0.001) at recurrence less frequently than the no surgery group (n=96). The secondary CRS group showed significantly better PFS (median, 33.7 vs. 7.2 months; P<0.001) and OS (P<0.001). Secondary CRS was associated with a significantly improved PFS (aHR, 0.297; 95% CI, 0.183–0.481; P<0.001) and OS (aHR, 0.276; 95% CI, 0.133–0.576; P=0.001). The BEV and non-BEV groups showed similar PFS and OS among the patients who underwent secondary CRS. The BEV group showed improved PFS and OS among patients who did not undergo surgery. Conclusions Our study results demonstrate the survival benefits of BEV and secondary CRS in patients with platinum-sensitive relapsed OCCC.