Clinical features and prognostic analysis of 247 patients with ovarian clear cell carcinoma (OCCC) and an exploration of the treatment of recurrent OCCC: A single-center study in China.

Abstract

e17548 Background: Ovarian clear cell carcinoma (OCCC) is relatively resistant to chemotherapy and has a worse prognosis than other ovary cancer. In this study, we reviewed the case files of OCCC in a single center to find its clinical characteristics and explore the treatment of recurrent cases, and the efficacy of immunotherapy. Methods: From August 2007 to August 2023 247 patients with OCCC were retrospectively involved. Univariate and multivariate Cox regression analyses were used to identify independent clinicopathological factors. The relapse OCCC were divided into four groups based on the different treatment who underwent chemotherapy or chemotherapy combined with surgery, bevacizumab, immune checkpoint inhibitors treatment. Kaplan–Meier curves were utilized to compare OS and DFS/PFS between the groups. Results: (1) 247 patients with OCCC were included, CA125 abnormality (> 35 U/ml) 65.2%, ascites cytology positive 10.1%, and the overall satisfactory reduction of tumor was 92.7%, CR and PR were 93.1 and 6.9%, respectively. 16.2% patients received more than 6 cycles of postoperative chemotherapy.(2)Univariate Cox regression analysis identified ascites (HR=4.012, 95% CI: 1.846 - 8.720, P<0.001), initial treatment effect (HR=2.714, 95% CI: 1.132 - 6.506, P=0.025), and chemotherapy cycles (HR=2.564, 95% CI: 1.402 - 4.689, P=0.002) were identified as independent prognostic factors for OS.(3)The patients who received chemotherapy cycles exceeding 6 cycles had worse prognosis(HR=3.01, 95%CI: 1.70-5.33, P<0.001), the result is the first proposal in our study.(4) Kaplan-Meier survival analysis showed that the OS of the chemotherapy combined with surgery relapse OCCC group was significantly better than the other three groups (HR=0.2732, 95%CI: 10.133-0.559, P=0.001). Subgroup analysis showed that relapse patients with satisfactory tumor reduction had more significant survival benefits(HR=3.86, 95%CI: 0.79-18.93, P=0.096).(5)The PFS of the chemotherapy combined with surgery group was also better than the other three groups (median PFS 25 months vs 8.5 months in chemotherapy vs12 months in chemotherapy combined immunotherapy vs 12 months in chemotherapy combined with bevacizumab). (6)4 patients who tested positive for PD-L1 received immune maintenance therapy after chemotherapy for 6-24months. There has been no recurrence since follow-up. Conclusions: Ascites, initial treatment effect and chemotherapy cycles were identified as independent prognostic factors for OCCC OS, chemotherapy combined with surgery for recurrent OCCC was significantly improving patient prognosis. For patients who achieve CR after initial treatment, if PD-L1 expression is positive, maintenance immunotherapy can be considered, but further studies with large samples are needed.