Kazuaki Takahashi

A retrospective study of dose-dense paclitaxel and carboplatin plus bevacizumab as first-line treatment of advanced epithelial ovarian cancer

This study compared the effectiveness, safety, and tolerability of dose-dense paclitaxel and carboplatin plus bevacizumab (ddTC+Bev) with ddTC for advanced ovarian cancer. We retrospectively analyzed the clinical records of 134 patients who received ddTC+Bev or ddTC as first-line chemotherapy for stage III-IV ovarian cancer. Progression-free survival as primary endpoint of this study was compared using the log-rank test. Cox proportional hazards model and propensity score matching (PSM) were used to analyze prognostic factors, and the frequency of adverse events was examined using the χ² test. We categorized 134 patients in the ddTC+Bev (n=57) and ddTC (n=77) groups who started treatment at four related institutions from November 2013 to December 2017. No patients used poly (ADP-ribose) polymerase inhibitors as the first line maintenance therapy. The progression-free survival (PFS) of the ddTC+Bev group had a significantly better prognosis than that of the ddTC group (hazard ratio [HR]=0.50; 95% confidence interval [CI]=0.32-0.79; p<0.003). Multivariate analysis showed that ddTC+Bev regimen was a prognostic factor. However, intergroup comparison using PSM revealed that the PFS of the ddTC+Bev group had a nonsignificantly better prognosis than that of the ddTC group (HR=0.70; 95% CI=0.41-1.20; p=0.189). Few adverse events above G3 were noted for ddTC+Bev, which were sufficiently tolerable. This study could not demonstrate that adding Bev to ddTC improves prognosis. Further studies with more cases are warranted.

Rethinking of treatment strategies and clinical management in ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC), with unique clinical and molecular characteristics compared with other histological types of epithelial ovarian cancer (EOC), behaves like a distinct entity and has a poorer prognosis than other EOC types, especially in advanced stages. In addition, OCCC comprises approximately 27% of all EOC cases in Japan, compared with 12% in Western countries. Historically, patients with OCCC have been eligible for chemotherapeutic and surgical trials of EOC. It has been difficult to evaluate the specific impact of these trials on the prognosis of women with OCCC because of its rarity and unique molecular characteristics. Recent studies of OCCC revealed significant molecular variations related to carcinogenesis and molecular targets that could directly facilitate patient stratification and subsequent precision medicine. Thus, treatment strategies specific for OCCC based on its clinical and molecular characteristics are urgently needed. In this review, we highlight the management and treatment of OCCC from clinical aspects.

Concurrent RB1 Loss and BRCA Deficiency Predicts Enhanced Immunologic Response and Long-term Survival in Tubo-ovarian High-grade Serous Carcinoma

Abstract Purpose: The purpose of this study was to evaluate RB1 expression and survival across ovarian carcinoma histotypes and how co-occurrence of BRCA1 or BRCA2 (BRCA) alterations and RB1 loss influences survival in tubo-ovarian high-grade serous carcinoma (HGSC). Experimental Design: RB1 protein expression was classified by immunohistochemistry in ovarian carcinomas of 7,436 patients from the Ovarian Tumor Tissue Analysis consortium. We examined RB1 expression and germline BRCA status in a subset of 1,134 HGSC, and related genotype to overall survival (OS), tumor-infiltrating CD8+ lymphocytes, and transcriptomic subtypes. Using CRISPR-Cas9, we deleted RB1 in HGSC cells with and without BRCA1 alterations to model co-loss with treatment response. We performed whole-genome and transcriptome data analyses on 126 patients with primary HGSC to characterize tumors with concurrent BRCA deficiency and RB1 loss. Results: RB1 loss was associated with longer OS in HGSC but with poorer prognosis in endometrioid ovarian carcinoma. Patients with HGSC harboring both RB1 loss and pathogenic germline BRCA variants had superior OS compared with patients with either alteration alone, and their median OS was three times longer than those without pathogenic BRCA variants and retained RB1 expression (9.3 vs. 3.1 years). Enhanced sensitivity to cisplatin and paclitaxel was seen in BRCA1-altered cells with RB1 knockout. Combined RB1 loss and BRCA deficiency correlated with transcriptional markers of enhanced IFN response, cell-cycle deregulation, and reduced epithelial–mesenchymal transition. CD8+ lymphocytes were most prevalent in BRCA-deficient HGSC with co-loss of RB1. Conclusions: Co-occurrence of RB1 loss and BRCA deficiency was associated with exceptionally long survival in patients with HGSC, potentially due to better treatment response and immune stimulation.