Clear cell carcinoma of the ovary: a retrospective multicentre experience of 254 patients with complete surgical staging

Targeting USP8 causes synthetic lethality through degradation of FGFR2 in ARID1A-deficient ovarian clear cell carcinoma

Over half of ovarian clear cell carcinoma (OCCC) cases exhibit deficiencies in the ARID1A gene, a chromatin remodeling complex component. OCCC is resistant to chemotherapy and challenging to treat, necessitating new drug treatment strategies. This study used a publicly available dependency factor database to identify synthetic lethal targets for ARID1A-deficient cancer. The DepMap portal was used to identify genes on which ARID1A-deficient cancer cell lines are highly dependent. Our analysis limited to ovarian cancer cell lines only identified the deubiquitinating enzyme USP8 as a synthetic lethal target in ARID1A-deficient OCCC cancer cell lines and mouse xenograft models. In addition, USP8 inhibitors were more selective for ARID1A-deficient cells than existing candidate drugs used in promising clinical trials for ARID1A-deficient cancers. Suppression of USP8 in ARID1A-deficient cells led to degradation of FGFR2 via the proteasome. Deficiency of ARID1A causes abnormalities in the STAT3 pathway, which is one of the downstream pathways of FGFR2, but suppression of USP8 attenuates phosphorylation of STAT3 pT705 and induces apoptosis. Taken together, our data suggest that USP8 is a novel therapeutic target for ARID1A-deficient OCCC and that USP8 inhibitors suppress FGFR2-STAT3 signaling.

Bevacizumab in frontline chemotherapy improved the survival outcome for advanced ovarian clear cell carcinoma: a multicenter retrospective analysis

OBJECTIVE

Advanced ovarian clear cell carcinoma (OCCC) is associated with poor outcomes owing to chemoresistance. Bevacizumab (Bev) is increasingly being used to treat advanced ovarian cancer; however, its efficacy in OCCC remains unclear. This study evaluated the treatment outcomes of frontline bevacizumab chemotherapy in patients with OCCC.

METHODS

This retrospective multi-institutional study included patients diagnosed with advanced OCCC at eight institutions in Japan between 2008 and 2018. Patients were categorized into pre and post-market groups based on the Bev approval dates. Progression-free survival (PFS) and overall survival (OS) were analyzed using univariate and multivariate methods. Additionally, patients were classified into Bev-treated (Bev+) and non-Bev-treated (Bev-) groups, and their prognoses were compared.

RESULTS

A total of 96 patients were in the pre-market group and 82 in the post-market group. The post-market group had a significantly higher proportion of patients with poor performance status and patients who underwent interval debulking surgery (p<0.01 and p<0.01, respectively). Univariate analysis demonstrated a better PFS in the post-market group (p=0.041). In multivariate analysis, better PFS (hazard ratio [HR]=0.52; p=0.002) and OS (HR=0.47; p=0.002) were observed in the post-market group than in the pre-market group. Bev+ patients had significantly better PFS and OS than Bev- patients in univariate (p<0.001 and p<0.001, respectively) and multivariate analyses (PFS: HR=0.36; p<0.001 and OS: HR=0.21; p=0.001, respectively).

CONCLUSION

Incorporating Bev into frontline chemotherapy may improve outcomes in patients with advanced OCCC.

Ovarian clear cell carcinoma: open questions on the management and treatment algorithm

Ovarian clear cell carcinoma (OCCC) accounts for ~10% of all epithelial ovarian cancers and is considered a different entity from the more common high-grade serous ovarian carcinoma (HGSC), with distinct clinical presentations, different risk, and prognostic factors, and specific molecular features. Most OCCCs are diagnosed at an early stage and show favorable outcomes, in contrast to those diagnosed at advanced stages, which exhibit intrinsic resistance to platinum-based chemotherapy regimens and a very poor prognosis. The standard treatment of advanced OCCC is currently based on primary debulking surgery followed by platinum-based chemotherapy according to recent international guidelines. However, these recommendations are extrapolated from several trials mainly featuring a large cohort of HGSC, with only a small minority of OCCC. Because of its rarity, many questions remain unanswered regarding the surgical and medical treatment. Lymph node staging, fertility-sparing treatment, the use of targeted therapies and radiotherapy as well as the adjuvant treatment for early-stage disease and second or further lines of chemotherapy are still under debate. This review aims to address these unresolved issues, by providing a comprehensive overview of the current data on this disease, and to suggest possible directions for future research.

Survival and biomarker analysis for cancer‑associated thromboembolism in ovarian clear cell carcinoma

The present study aimed to investigate the impact of cancer-associated thromboembolism (CAT) on the survival and biomarkers of ovarian clear cell carcinoma (OCCC). Patients with OCCC who underwent surgery at the National Defense Medical College Hospital (Tokorozawa, Japan) between January 2000 and December 2019 were included in the current study. Associations among CAT, clinicopathological features and prognosis were retrospectively compared. Furthermore, immunohistochemical staining was conducted in all patients to compare differences between patients with and without CAT. Among 111 patients with OCCC, 20 patients (18.0%) had CAT complications. CAT was detected in 12 patients (10.8%) before primary treatment and in 8 patients (7.2%) after primary surgery. Patients with CAT experienced more tumor recurrence (P=0.048) and platinum resistance (P=0.025), had worse progression-free survival (PFS; P<0.01) and overall survival (OS; P<0.01), and multivariate analysis showed that CAT was a prognostic factor for worse PFS [hazard ratio (HR)=2.10, P=0.039] and OS (HR=4.26, P<0.01). Moreover, immunohistochemical analysis revealed that more OCCC cases with CAT were positive for tissue factor (TF; P=0.030) and phosphorylated-Janus kinase 2 (JAK2; P=0.034) expression than those without CAT. In conclusion, CAT may be associated with platinum resistance and poor prognosis in patients with OCCC. Furthermore, TF and JAK2 could be considered potential novel therapeutic targets for OCCC complicated by CAT.

Comparison of Treatment Outcomes Between First-Line Chemotherapy With or Without Bevacizumab for Advanced Ovarian Clear Cell Carcinoma (Tohoku Gynecologic Cancer Unit: TGCU-RS001A Study)

Objective: The usefulness of bevacizumab (BEV) as first-line chemotherapy for advanced ovarian clear cell carcinoma (CCC) was retrospectively evaluated at Tohoku Gynecologic Cancer Unit institutions. Patients and Methods: A total of 81 patients (52 patients without BEV and 29 with BEV) with advanced ovarian CCC who received initial platinum-based chemotherapy were enrolled. We selected 26 patients each without and with BEV according to propensity score matching methods, and compared the platinum-resistant recurrence rate, response rate, progression-free survival (PFS), overall survival (OS), and adverse events between the two groups. Results: The objective response rates for the patients with measurable disease in the non-BEV and BEV groups were 60.0% and 95.5%, respectively (p = 0.007). The recurrence of platinum-resistant patients was observed in 50.0% of the non-BEV group and 23.1% of the BEV group (p = 0.117). The median PFS was 12 and 22 months, respectively (p = 0.034), and the median OS was 32 and 47 months, respectively (p = 0.223). In the BEV group, grade 3 hypertension and proteinuria occurred in two patients, and thrombosis and carboplatin hypersensitivity occurred in one patient. Grade 4 gastrointestinal perforation occurred in one patient. Conclusions: First-line chemotherapy with BEV in advanced CCC showed the potential for high response rates and improved PFS.

Status and development of research on clear cell carcinoma of the ovary-a visualization-based bibliometric analysis

Background

Clear cell carcinoma of the ovary (CCCO) is a relatively rare type of epithelial ovarian cancer (EOC) that has unique biological characteristics and clinical features. Researchers have paid less attention to this disease than to other types of EOCs. However, in recent years, research in this area has still progressed. In this paper, a bibliometric analysis is used to integrate and analyse the literature in the field of CCCO in the past 20 years to determine research development, better understand the current status of research, and provide a reference for future study directions in this field.

Methods

With CCCO as the research subject, relevant publications indexed in the Web of Science (WOS) core dataset from September 2003 to September 2023 were retrieved. After screening the publications, we used EXCEL, VOSviewer, CiteSpace, Charticulator, Gephi, OriginPro and other tools to perform in-depth analyses of and to visualize the data.

Results

Through a comprehensive analysis of the literature in this field, we found that research on CCCO experienced a relatively rapid increase in 2006 and is now in a period of relatively high fluctuation. The quality of the literature in this field is generally high. In this field, countries in East Asia and North America play core roles, with Japan accounting for the most studies. A stable research group has been formed in this field, and extensive collaboration has occurred among the various research groups. In the past 20 years, basic research and clinical research in the field of CCCO have developed together, and a healthy development model in which basic and clinical research promote each other has formed. Research in this field has been continuously developed from a preliminary understanding of clinical features to in-depth explorations of the pathogenesis and the continuous optimization of treatment methods. The key molecular events in the pathogenesis and development of this disease and the application of novel antitumour drugs for this disease are the current research focuses and the future development direction in this field.

Conclusions

Research on CCCO has progressed significantly in the past 20 years, but there are still many important issues regarding its pathogenesis and treatment that need to be addressed, and therefore, more research in this area should be conducted in the future. The study of key molecular events and the use of novel antitumour drugs are future development directions in this field.

Exploration and prognostic analysis of two types of high-risk ovarian cancers: clear cell vs. serous carcinoma: a population-based study

BACKGROUND

Ovarian clear cell carcinoma (OCCC) is a rare pathological histotype in ovarian cancer, while the survival rate of advanced OCCC (Stage III-IV) is substantially lower than that of the advanced serous ovarian cancer (OSC), which is the most common histotype. The goal of this study was to identify high-risk OCCC by comparing OSC and OCCC, with investigating potential risk and prognosis markers.

METHODS

Patients diagnosed with ovarian cancer from 2009 to 2018 were identified from the Surveillance, Epidemiology, and End Results (SEER) Program. Logistic and Cox regression models were used to identify risk and prognostic factors in high-risk OCCC patients. Cancer-specific survival (CSS) and overall survival (OS) were assessed using Kaplan-Meier curves. Furthermore, Cox analysis was employed to build a nomogram model. The performance evaluation results were displayed using the C-index, calibration plots, receiver operating characteristic (ROC) curve, and decision curve analysis (DCA). Immunohistochemically approach was used to identify the expression of the novel target (GPC3).

RESULTS

In the Cox analysis for advanced OCCC, age (45-65 years), tumor numbers (total number of in situ/malignant tumors for patient), T3-stage, bilateral tumors, and liver metastases could be defined as prognostic variables. Nomogram showed good predictive power and clinical practicality. Compared with OSC, liver metastases had a stronger impact on the prognosis of patients with OCCC. T3-stage, positive distant lymph nodes metastases, and lung metastases were risk factors for developing liver metastases. Chemotherapy was an independent prognostic factor for patient with advanced OCCC, but had no effect on CSS in patients with liver metastases (p = 0.0656), while surgery was significantly related with better CSS in these patients (p < 0.0001) (p = 0.0041). GPC3 expression was detected in all tissue sections, and GPC3 staining was predominantly found in the cytoplasm and membranes.

CONCLUSION

Advanced OCCC and OCCC with liver metastases are two types of high-risk OCCC. The constructed nomogram exhibited a satisfactory survival prediction for patients with advanced OCCC. GPC3 immunohistochemistry is expected to accumulate preclinical evidence to support the inclusion of GPC3 in OCCC targeted therapy.

The impact of lymphadenectomy on the survival outcomes of ovarian clear cell carcinoma: A retrospective study of the SEER database and Chinese registry

BACKGROUND

Ovarian clear cell carcinoma (OCCC) is a rare pathological type of ovarian cancer with a poor prognosis, and lymphadenectomy is controversial in patients with OCCC. The objective of this study was to evaluate the impact of lymphadenectomy on the prognosis of patients with OCCC.

METHODS

In this retrospective study, we collected data from the Surveillance, Epidemiology and End Results (SEER) database and institutional registries in China. The SEER cohort included 1777 women diagnosed with OCCC between 2010 and 2019, while the Chinese cohort included 199 women diagnosed between April 2004 and April 2021. Recurrence-free survival (RFS) and overall survival (OS) were studied using Kaplan-Meier curve and Cox regression analysis. We also employed propensity score matching (PSM) to adjust for baseline imbalances between the lymphadenectomy group and the no-lymphadenectomy group.

RESULTS

Multivariate cox regression analysis showed that lymphadenectomy was not associated with better overall survival (OS) in either early (hazard ratio [HR] 0.84[0.50-1.43], p = 0.528) or advanced (HR 0.78[0.50-1.21], p = 0.270) patients in the SEER cohort after PSM. Additionally, in the Kaplan-Meier curve analysis, lymphadenectomy did not significantly improve OS in both early (p = 0.28) and advanced (p = 0.49) patients in the SEER cohort after PSM. Similarly, in the Chinese cohort, lymphadenectomy had no significant effect on OS (early p = 0.22; advanced p = 0.61) or RFS (early p = 0.18; advanced p = 0.83) in both early and advanced patients.

CONCLUSION

In completely homogeneous groups, lymphadenectomy in women diagnosed with OCCC had no effect on either recurrence-free survival or overall survival compared to patients without lymphadenectomy.

From clinical management to personalized medicine: novel therapeutic approaches for ovarian clear cell cancer

Ovarian clear-cell cancer is a rare subtype of epithelial ovarian cancer with unique clinical and biological features. Despite optimal cytoreductive surgery and platinum-based chemotherapy being the standard of care, most patients experience drug resistance and a poor prognosis. Therefore, novel therapeutic approaches have been developed, including immune checkpoint blockade, angiogenesis-targeted therapy, ARID1A synthetic lethal interactions, targeting hepatocyte nuclear factor 1β, and ferroptosis. Refining predictive biomarkers can lead to more personalized medicine, identifying patients who would benefit from chemotherapy, targeted therapy, or immunotherapy. Collaboration between academic research groups is crucial for developing prognostic outcomes and conducting clinical trials to advance treatment for ovarian clear-cell cancer. Immediate progress is essential, and research efforts should prioritize the development of more effective therapeutic strategies to benefit all patients.

The impact of lymphadenectomy on ovarian clear cell carcinoma: a systematic review and meta-analysis

BACKGROUND

Ovarian clear cell carcinoma (OCCC) shares treatment strategies with epithelial ovarian cancer (EOC). Due to OCCC's rarity, there's a lack of prospective studies on its surgery, resulting in heterogeneous and limited existing data. This study aims to clarify the prognostic significance of lymphadenectomy in OCCC patients.

METHODS

We systematically searched Web of Science, Scopus, PubMed, and Google Scholar until July 2023 for studies investigating lymphadenectomy's effects on OCCC patients. We calculated pooled hazard ratios (HR) with 95% confidence intervals (CI). This study is registered in PROSPERO (CRD42021270460).

RESULTS

Among 444 screened articles, seven studies (2883 women) met inclusion criteria. Our analysis revealed that lymphadenectomy significantly improved disease-specific survival (DSS) (HR = 0.76, 95%CI = 0.60-0.95, P = 0.02) and disease-free survival (DFS) (HR = 0.58, 95%CI = 0.34-0.99, P = 0.05). However, it did not significantly affect overall survival (OS) (HR = 0.80, 95%CI = 0.60-1.06, P = 0.12) or progression-free survival (PFS) (HR = 0.95, 95%CI = 0.64-1.42, P = 0.79). Notably, some earlier studies reported no survival benefit, warranting cautious interpretation.

CONCLUSION

Lymphadenectomy does not significantly enhance OS and PFS for OCCC but does improve DFS and DSS. Tailoring treatment to individual patient profiles is imperative for optimal outcomes. Precise preoperative or intraoperative lymph node metastasis detection is essential for identifying candidates benefiting from lymphadenectomy. Collaborative international efforts and an OCCC database are pivotal for refining future treatment strategies.

Ovarian Cancer: From Precursor Lesion Identification to Population-Based Prevention Programs

Epithelial ovarian cancer (EOC) is a heterogeneous group of malignancies, including high-grade serous ovarian cancer (HGSC). HGSC is often diagnosed at advanced stages and is linked to TP53 variants. While BRCA variants elevate risk, most HGSC cases occur in individuals without known genetic variants, necessitating prevention strategies for people without known high-risk genetic variants. Effective prevention programs are also needed due to the lack of traditional screening options. An emerging primary prevention strategy is opportunistic salpingectomy, which involves removing fallopian tubes during another planned pelvic surgery. Opportunistic salpingectomy offers a safe and cost-effective preventative option that is gaining global adoption. With the publication of the first cohort study of patients who underwent salpingectomy, specifically for cancer prevention, attention has turned to broadening opportunities for salpingectomy in addition to more targeted approaches. Prevention opportunities are promising with increasing adoption of salpingectomy and the increased understanding of the etiology of the distinct histotypes of ovarian cancer. Yet, further research on targeted risk-reducing salpingectomy with thoughtful consideration of equity is necessary to reduce death and suffering from ovarian cancer.

A preoperative nomogram incorporating CT to predict the probability of ovarian clear cell carcinoma

OBJECTIVES

To evaluate clinical, laboratory, and radiological variables from preoperative contrast-enhanced computed tomography (CECT) for their ability to distinguish ovarian clear cell carcinoma (OCCC) from non-OCCC and to develop a nomogram to preoperatively predict the probability of OCCC.

METHODS

This IRB-approved, retrospective study included consecutive patients who underwent surgery for an ovarian tumor from 1/1/2000 to 12/31/2016 and CECT of the abdomen and pelvis ≤90 days before primary debulking surgery. Using a standardized form, two experienced oncologic radiologists independently analyzed imaging features and provided a subjective 5-point impression of the probability of the histological diagnosis. Nomogram models incorporating clinical, laboratory, and radiological features were created to predict histological diagnosis of OCCC over non-OCCC.

RESULTS

The final analysis included 533 patients with surgically confirmed OCCC (n = 61) and non-OCCC (n = 472); history of endometriosis was more often found in patients with OCCC (20% versus 3.6%; p < 0.001), while CA-125 was significantly higher in patients with non-OCCC (351 ng/mL versus 70 ng/mL; p < 0.001). A nomogram model incorporating clinical (age, history of endometriosis and adenomyosis), laboratory (CA-125) and imaging findings (peritoneal implant distribution, morphology, laterality, and diameter of ovarian lesion and of the largest solid component) had an AUC of 0.9 (95% CI: 0.847, 0.949), which was comparable to the AUCs of the experienced radiologists' subjective impressions [0.8 (95% CI: 0.822, 0.891) and 0.9 (95% CI: 0.865, 0.936)].

CONCLUSIONS

A presurgical nomogram model incorporating readily accessible clinical, laboratory, and CECT variables was a powerful predictor of OCCC, a subtype often requiring a distinctive treatment approach.

Genetic characteristics of platinum-sensitive ovarian clear cell carcinoma

OBJECTIVE

Most ovarian clear cell carcinomas are resistant to platinum-based chemotherapy, while a small subset shows a positive response. The aim of this study was to clarify the clinical, pathological and genetic characteristics of platinum-sensitive ovarian clear cell carcinomas.

METHODS

The study included 53 patients with stage III-IV ovarian clear cell carcinoma who had residual tumours after primary surgery and received platinum-based therapy between 2009 and 2018. A retrospective examination of platinum sensitivity was performed using the criterion of ≥6 months from the last day of first-line platinum therapy until recurrence/progression. Cases determined to be platinum-sensitive were subjected to immunohistochemical staining, genomic analyses using target sequencing (i.e. NCC Oncopanel) and homologous recombination deficiency (myChoice® HRD Plus) assays.

RESULTS

Of the 53 stage III-IV ovarian clear cell carcinoma cases, 11 (21%) were platinum-sensitive. These cases showed better progression-free and overall survival than platinum-resistant cases (hazard ratio = 0.16, P < 0.001). Among the seven sensitive cases whose tumour tissues were available for molecular profiling, five were pure ovarian clear cell carcinoma based on pathological and genetic features, whereas the remaining two cases were re-diagnosed as high-grade serous ovarian carcinoma. The pure ovarian clear cell carcinomas lacked BRCA1 and BRCA2 mutations, consistent with the absence of the homologous recombination deficiency phenotype, whereas two cases (40%) had ATM mutations. By contrast, the two high-grade serous ovarian carcinoma cases had BRCA1 or BRCA2 mutations associated with the homologous recombination deficiency phenotype.

CONCLUSION

The subset of platinum-sensitive ovarian clear cell carcinomas includes a majority with pure ovarian clear cell carcinoma features that lack the homologous recombination deficiency phenotype.

Temozolomide Sensitizes ARID1A-Mutated Cancers to PARP Inhibitors

ARID1A is a subunit of SWI/SNF chromatin remodeling complexes and is mutated in many types of human cancers, especially those derived from endometrial epithelium, including ovarian and uterine clear cell carcinoma (CCC) and endometrioid carcinoma (EMCA). Loss-of-function mutations in ARID1A alter epigenetic regulation of transcription, cell-cycle checkpoint control, and DNA damage repair. We report here that mammalian cells with ARID1A deficiency harbor accumulated DNA base lesions and increased abasic (AP) sites, products of glycosylase in the first step of base excision repair (BER). ARID1A mutations also delayed recruitment kinetics of BER long-patch repair effectors. Although ARID1A-deficient tumors were not sensitive to monotherapy with DNA-methylating temozolomide (TMZ), the combination of TMZ with PARP inhibitors (PARPi) potently elicited double-strand DNA breaks, replication stress, and replication fork instability in ARID1A-deficient cells. The TMZ and PARPi combination also significantly delayed in vivo growth of ovarian tumor xenografts carrying ARID1A mutations and induced apoptosis and replication stress in xenograft tumors. Together, these findings identified a synthetic lethal strategy to enhance the response of ARID1A-mutated cancers to PARP inhibition, which warrants further experimental exploration and clinical trial validation.

SIGNIFICANCE

The combination of temozolomide and PARP inhibitor exploits the specific DNA damage repair status of ARID1A-inactivated ovarian cancers to suppress tumor growth.

Transcriptomic analyses of ovarian clear-cell carcinoma with concurrent endometriosis

Introduction

Endometriosis, a benign inflammatory disease whereby endometrial-like tissue grows outside the uterus, is a risk factor for endometriosis-associated ovarian cancers. In particular, ovarian endometriomas, cystic lesions of deeply invasive endometriosis, are considered the precursor lesion for ovarian clear-cell carcinoma (OCCC).

Methods

To explore this transcriptomic landscape, OCCC from women with pathology-proven concurrent endometriosis (n = 4) were compared to benign endometriomas (n = 4) by bulk RNA and small-RNA sequencing.

Results

Analysis of protein-coding genes identified 2449 upregulated and 3131 downregulated protein-coding genes (DESeq2, P< 0.05, log2 fold-change > |1|) in OCCC with concurrent endometriosis compared to endometriomas. Gene set enrichment analysis showed upregulation of pathways involved in cell cycle regulation and DNA replication and downregulation of pathways involved in cytokine receptor signaling and matrisome. Comparison of pathway activation scores between the clinical samples and publicly-available datasets for OCCC cell lines revealed significant molecular similarities between OCCC with concurrent endometriosis and OVTOKO, OVISE, RMG1, OVMANA, TOV21G, IGROV1, and JHOC5 cell lines. Analysis of miRNAs revealed 64 upregulated and 61 downregulated mature miRNA molecules (DESeq2, P< 0.05, log2 fold-change > |1|). MiR-10a-5p represented over 21% of the miRNA molecules in OCCC with endometriosis and was significantly upregulated (NGS: log2fold change = 4.37, P = 2.43e-18; QPCR: 8.1-fold change, P< 0.05). Correlation between miR-10a expression level in OCCC cell lines and IC50 (50% inhibitory concentration) of carboplatin in vitro revealed a positive correlation (R2 = 0.93). MiR-10a overexpression in vitro resulted in a significant decrease in proliferation (n = 6; P< 0.05) compared to transfection with a non-targeting control miRNA. Similarly, the cell-cycle analysis revealed a significant shift in cells from S and G2 to G1 (n = 6; P< 0.0001). Bioinformatic analysis predicted that miR-10a-5p target genes that were downregulated in OCCC with endometriosis were involved in receptor signaling pathways, proliferation, and cell cycle progression. MiR-10a overexpression in vitro was correlated with decreased expression of predicted miR-10a target genes critical for proliferation, cell-cycle regulation, and cell survival including [SERPINE1 (3-fold downregulated; P< 0.05), CDK6 (2.4-fold downregulated; P< 0.05), and RAP2A (2-3-fold downregulated; P< 0.05)].

Discussion

These studies in OCCC suggest that miR-10a-5p is an impactful, potentially oncogenic molecule, which warrants further studies.

Differential molecular pathway expression according to chemotherapeutic response in ovarian clear cell carcinoma

OBJECTIVE

Ovarian clear cell carcinoma (OCCC) is a distinct entity from epithelial ovarian cancer. The prognosis of advanced and recurrent disease is very poor due to resistance to chemotherapeutic agents. Our aim was to explore the molecular alterations among OCCC patients with different chemotherapeutic responses and to obtain insights into potential biomarkers.

METHODS

Twenty-four OCCC patients were included in this study. The patients were divided into two groups based on the relapse time after the first-line platinum-based chemotherapy: the platinum-sensitive group (PS) and the platinum-resistant group (PR). Gene expression profiling was performed using NanoString nCounter PanCancer Pathways Panel.

RESULTS

Gene expression analysis comparing PR vs. PS identified 32 differentially expressed genes: 17 upregulated genes and 15 downregulated genes. Most of these genes are involved in the PI3K, MAPK and Cell Cycle-Apoptosis pathways. In particular, eight genes are involved in two or all three pathways.

CONCLUSION

The dysregulated genes in the PI3K, MAPK, and Cell Cycle-Apoptosis pathways identified and postulated mechanisms could help to probe biomarkers of OCCC platinum sensitivity, providing a research basis for further exploration of targeted therapy.

Immune-Hot tumor features associated with recurrence in early-stage ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC) is a distinct histotype of ovarian cancer, which usually presages a worse prognosis upon recurrence. Identifying patients at risk for relapse is an unmet need to improve outcomes. A retrospective cohort analysis of 195 early-stage OCCC patients diagnosed between January 2011 and December 2019 at National Taiwan University Hospital was conducted to identify prognostic factors for recurrence, progression-free survival (PFS) and overall survival (OS). Molecular profiling of tumors was performed in a case-controlled cohort matched for adjuvant therapy for biomarker discovery. Multivariate Cox proportional hazard model revealed that paclitaxel-based chemotherapy was associated with better PFS than nonpaclitaxel chemotherapy (HR = 0.19, P = .006). The addition of bevacizumab was associated with better PFS, compared to no bevacizumab (HR = 0.09, P = .02). Neither showed significant improvement in OS. Recurrence is associated with an Immune-Hot tumor feature (P = .03), the CTLA-4-high subtype (P = .01) and increased infiltration of immune cells in general. The Immune-Hot feature (HR = 3.39, P = .005) and the CTLA-4-high subtype (HR = 2.13, P = .059) were associated with worse PFS. Immune-Hot tumor features could prognosticate recurrence in early-stage OCCC.

Prediction of Surgical Outcome in Advanced Ovarian Cancer by Imaging and Laparoscopy: A Narrative Review

Maximal-effort upfront or interval debulking surgery is the recommended approach for advanced-stage ovarian cancer. The role of diagnostic imaging is to provide a systematic and structured report on tumour dissemination with emphasis on key sites for resectability. Imaging methods, such as pelvic and abdominal ultrasound, contrast-enhanced computed tomography, whole-body diffusion-weighted magnetic resonance imaging and positron emission tomography, yield high diagnostic performance for diagnosing bulky disease, but they are less accurate for depicting small-volume carcinomatosis, which may lead to unnecessary explorative laparotomies. Diagnostic laparoscopy, on the other hand, may directly visualize intraperitoneal involvement but has limitations in detecting tumours beyond the gastrosplenic ligament, in the lesser sac, mesenteric root or in the retroperitoneum. Laparoscopy has its place in combination with imaging in cases where ima-ging results regarding resectability are unclear. Different imaging models predicting tumour resectability have been developed as an adjunctional objective tool. Incorporating results from tumour quantitative analyses (e.g., radiomics), preoperative biopsies and biomarkers into predictive models may allow for more precise selection of patients eligible for extensive surgery. This review will discuss the ability of imaging and laparoscopy to predict non-resectable disease in patients with advanced ovarian cancer.

New therapies for clear cell ovarian carcinoma

Ovarian clear cell carcinoma is a rare subtype of epithelial ovarian cancer with unique clinicopathological features. The most common genetic aberration observed is loss of function ARID1A mutations. Advanced and recurrent ovarian clear cell carcinoma is characterized by resistance to standard-of-care cytotoxic chemotherapy and a poor prognosis. Despite the distinct molecular features of ovarian clear cell carcinoma, current treatments for this subtype of epithelial ovarian cancer are based on clinical trials which predominantly recruited patients with high grade serous ovarian carcinoma. These factors have encouraged researchers to develop novel treatment strategies specifically for ovarian clear cell carcinoma which are currently being tested in the context of clinical trials. These new treatment strategies currently focus on three key areas: immune checkpoint blockade, targeting angiogenesis, and exploiting ARID1A synthetic lethal interactions. Rational combinations of these strategies are being assessed in clinical trials. Despite the progress made in identifying new treatments for ovarian clear cell carcinoma, predictive biomarkers to better define those patients likely to respond to new treatments remain to be elucidated. Additional future challenges which may be addressed through international collaboration include the need for randomized trials in a rare disease and establishing the relative sequencing of these novel treatments.

Advanced Stage Clear Cell Ovarian Carcinoma Mimicking Uterine Sarcoma Without Gross Residual Tumor During Primary Surgery: A Case Report

Background:

Clear cell ovarian carcinoma is rare and accounts for 1%-12% of ovarian epithelial carcinomas, depending on ethnicity. The prevalence of clear cell ovarian carcinoma in Asian, White, and Black women is 11.1%%, 4.8%, and 3.1%, respectively. Magnetic resonance imaging (MRI) shows that clear cell ovarian carcinomas are typically unilocular cyst-solid (34.9%) or multilocular-solid (41.4%); only 23.7% are solid with papillary projections. MRI can detect clear cell ovarian carcinoma with a sensitivity and specificity of 90% and 87%, respectively. Notably, sometimes ovarian masses have a solid feature and should be differentiated from uterine masses. Clear cell ovarian carcinoma has a better prognosis compared to serous carcinoma when diagnosed at an early stage, but it has a poorer prognosis at an advanced stage. The absence of a residual tumor is a favorable prognostic factor in patients with advanced-stage clear cell ovarian carcinoma. Herein, we present a case in which clear cell ovarian carcinoma was misdiagnosed as uterine sarcoma because imaging showed a mass with a solid uterine-like and necrotic area. In the present case, cytoreductive surgery was performed to remove the entire tumor and its infiltration to the sigmoid colon and left ureter. Hence, the patient had a better prognosis.

Case report:

A 57-year-old Indonesian woman presented to our hospital (Dr. Soetomo General Hospital) with post-menopausal bleeding, a large solid pelvic mass, and abdominal discomfort. The patient was diagnosed with uterine sarcoma due to the solid feature observed during ultrasonography and MRI. During the surgery, the mass was observed to originate from the left ovary, and primary debulking surgery with a multidisciplinary team was performed with zero residual tumor tissue. The tumor was histopathologically confirmed as clear cell carcinoma.

Conclusion:

MRI of clear cell ovarian carcinoma can be misdiagnosed as uterine sarcoma due to its solid feature. Additionally, the enlarged mass distorts the anatomical landmarks. Surgery with no residual tumor improves the prognosis for advanced-stage clear cell ovarian carcinoma.

Phase II study of gemcitabine, cisplatin, and bevacizumab for first recurrent and refractory ovarian clear cell carcinoma Kansai Clinical Oncology Group-G1601

Patients with advanced ovarian clear cell carcinoma (CCC) have a poor prognosis in the absence of an effective standard treatment. Combination therapy with gemcitabine, cisplatin, and bevacizumab (GPBev) is promising for ovarian CCC. Thus, we conducted a multi-institutional, phase II trial in Japan to examine the efficacy and safety of GPBev for CCC. This is the first study on the use of GPBev for CCC. Eighteen patients (median age, 56.5 years) with pathologically confirmed first recurrent or refractory CCC and having evaluable regions, as assessed using RECIST, were recruited between January 2017 and May 2019. Gemcitabine (1000 mg/m2), cisplatin (40 mg/m2), and bevacizumab (10 mg/kg) were administered intravenously on days 1 and 15, every 28 days, for 6-10 cycles, until disease progression or intolerable toxicity. The primary endpoint was overall response rate (ORR). The secondary endpoints included disease control rate (DCR) and adverse events (AEs). Fifteen patients (83.3%) completed 6-10 cycles of treatment; three patients (two with AEs and one with progressive disease) did not. The ORR was 61.1% [complete response (CR) 3 and partial response (PR) 8] and DCR was 88.9% (CR 3, PR 8, and stable disease 5). Grade 3 and 4 hematological AEs were observed in 16.7 and 5.6% of the patients, respectively. Nonhematological AEs of grades 3 and 4 were observed in 27.8 and 5.6% of the patients, respectively. GPBev is a promising therapy for CCC owing to the high ORR and acceptable toxicity for the first recurrence and refractory CCC.

Developing and validating a prognostic nomogram for ovarian clear cell carcinoma patients: A retrospective comparison of lymph node staging schemes with competing risk analysis

Purpose

Lymph node (LN) involvement is a key factor in ovarian clear cell carcinoma (OCCC) although, there several indicators can be used to define prognosis. This study examines the prognostic performances of each indicator for OCCC patients by comparing the number of lymph nodes examined (TNLE), the number of positive lymph nodes (PLN), lymph node ratio (LNR), and log odds of metastatic lymph nodes (LODDS).

Methods

1,300 OCCC patients who underwent lymphadenectomy between 2004 and 2015 were extracted from the Surveillance Epidemiology and End Results (SEER) database. Primary outcomes were Overall Survival (OS) and the cumulative incidence of Cancer-Specific Survival (CSS). Kaplan–Meier’s and Fine-Gray’s tests were implemented to assess OS and CSS rates. After conducting multivariate analysis, nomograms using OS and CSS were constructed based upon an improved LN system. Each nomograms’ performance was assessed using Receiver Operating Characteristics (ROC) curves, calibration curves, and the C-index which were compared to traditional cancer staging systems.

Results

Multivariate Cox’s regression analysis was used to assess prognostic factors for OS, including age, T stage, M stage, SEER stage, and LODDS. To account for the CSS endpoint, a proportional subdistribution hazard model was implemented which suggested that the T stage, M stage, SEER stage, and LNR are all significant. This enabled us to develop a LODDS-based nomogram for OS and a LNR-based nomogram for CSS. C-indexes for both the OS and CSS nomograms were higher than the traditional American Joint Committee on Cancer (AJCC), 8th edition, staging system. Area Under the Curve (AUC) values for predicting 3- and 5-year OS and CSS between nomograms also highlighted an improvement upon the AJCC staging system. Calibration curves also performed with consistency, which was verified using a validation cohort.

Conclusions

LODDS and LNR may be better predictors than N stage, TNLE, and PLNs. For OCCC patients, both the LODDS-based and LNR-based nomograms performed better than the AJCC staging system at predicting OS and CSS. However, further large sample, real-world studies are necessary to validate the assertion.

Clear cell carcinoma palisading in a focus of endometriosis on the uterine serosa – A case report and review of the literature

Background

Case Presentation

Conclusion

•

Clear cell carcinoma secondary to malignant endometriosis is a distinct biological entity

•

Immunohistochemistry is useful in differentiating from a primary gynaecological cancer.

•

Patients may be asymptomatic or present with a pelvic mass, abnormal uterine bleeding, constipation or haematuria.

•

Endometriosis-associated neoplasia is staged surgically.

•

A combination of adjuvant chemotherapy and radiotherapy is required for high-risk histological subtypes.

The worsening impact of programmed cell death ligand 1 in ovarian clear cell carcinomas

PURPOSE

To investigate the clinical significance of programmed cell death ligand 1 (PD-L1) expression in ovarian clear cell carcinoma (CCC).

MATERIALS AND METHODS

Patients with CCC who underwent primary surgery at our hospital between 1984 and 2014 were enrolled in this study. PD-L1 and mismatch repair (MMR) protein expression in tumor cells, tumor-infiltrating lymphocytes (TILs), including cluster of differentiation (CD) 8, CD4, forkhead box P3 (FOXP3), programmed cell death 1 (PD-1), and BAF250a, were evaluated using immunohistochemistry. The association between PD-L1 expression, clinicopathological features, prognosis, and expression of several proteins was investigated.

RESULTS

Of the 125 patients with CCC, 17 had negative PD-L1 and 108 had positive PD-L1. Patients with positive PD-L1 expression showed a lower response to chemotherapy (p = 0.01). In addition, patients with positive PD-L1 showed worse progression-free survival (PFS, p = 0.01) and overall survival (OS, p = 0.01) than that in patients with negative PD-L1 expression. Multivariate analyses for PFS and OS showed that PD-L1 expression was an independent prognostic factor for PFS (hazard ratio [HR] 7.81, p < 0.01) and OS (HR 12.90, p < 0.01). PD-L1 expression was not associated with the expression of several TILs or proteins.

CONCLUSION

The expression of PD-L1 was related to a lower response to chemotherapy and worse prognosis in CCC. These results may be useful for the development of new treatments.

Differential roles of the Wip1-p38-p53 DNA damage response pathway in early/advanced-stage ovarian clear cell carcinomas

Background

Ovarian clear cell carcinoma (OCCC) is one of the most lethal types of ovarian cancer. Early-stage OCCC can be cured by surgery; however, advanced-stage disease shows poor prognosis due to chemoresistance unlike the more common high-grade serous carcinoma.

Methods

We explored the differential roles of the Wip1–p38–p53 DNA damage response pathway in respective early- or advanced-stage OCCC by immunohistochemistry of Wip1, phospho-p38, p53, and phospho-p53 from consecutive 143 patients.

Results

High Wip1 expression correlated with positive p53 (p=0.011), which in turn correlated with low nuclear phospho-p38 expression (p=0.0094). In the early stages, positive p53 showed trends toward worse overall survival (OS) (p=0.062), whereas in the advanced stages, high Wip1 correlated with worse OS (p=0.0012). The univariate and multivariate analyses of prognostic factors indicated that high Wip1 was significant and independent for worse OS (p=0.011) in the advanced stages, but not in the early stages. Additionally, high Wip1 showed trends toward shorter treatment-free interval (TFI) in the advanced stages, but not in the early stages (p=0.083 vs. 0.93). Furthermore, high Wip1 was significantly associated with positive p53 only in the patients with shorter TFI (<6 months), but not in those with longer TFI (≥6 months) (p=0.036 vs. 0.34).

Conclusions

Wip1 appears to play a crucial role for the prognosis of OCCC through chemoresistance specifically in the advanced stages, implicating that Wip1 possibly serves as a reasonable therapeutic target for improving chemoresistance and poor prognosis of advanced-stage OCCC.

Therapeutic Strategies Focused on Cancer-Associated Hypercoagulation for Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is associated with chemotherapy resistance and poor prognosis, especially in advanced cases. Although comprehensive genomic analyses have clarified the significance of genomic alterations such as ARID1A and PIK3CA mutations in OCCC, therapeutic strategies based on genomic alterations have not been confirmed. On the other hand, OCCC is clinically characterized by a high incidence of thromboembolism. Moreover, OCCC specifically shows high expression of tissue factor and interleukin-6, which play a critical role in cancer-associated hypercoagulation and may be induced by OCCC-specific genetic alterations or the endometriosis-related tumor microenvironment. In this review, we focused on the association between cancer-associated hypercoagulation and molecular biology in OCCC. Moreover, we reviewed the effectiveness of candidate drugs targeting hypercoagulation, such as tissue factor- or interleukin-6-targeting drugs, anti-inflammatory drugs, anti-hypoxia signaling drugs, anticoagulants, and combined immunotherapy with these drugs for OCCC. This review is expected to contribute to novel basic research and clinical trials for the prevention, early detection, and treatment of OCCC focused on hypercoagulation.

CRISPR/Cas9 Screening for Identification of Genes Required for the Growth of Ovarian Clear Cell Carcinoma Cells

Epithelial ovarian cancer is classified into four major histological subtypes: serous, clear cell, endometrioid and mucinous. Ovarian clear cell carcinoma (OCCC) responds poorly to conventional chemotherapies and shows poor prognosis. Thus, there is a need to develop new drugs for the treatment of OCCC. In this study, we performed CRISPR/Cas9 screens against OCCC cell lines and identified candidate genes important for their proliferation. We found that quite different genes are required for the growth of ARID1A and PIK3CA mutant and wild-type OCCC cell lines, respectively. Furthermore, we found that the epigenetic regulator KDM2A and the translation regulator PAIP1 may play important roles in the growth of ARID1A and PIK3CA mutant, but not wild-type, OCCC cells. The results of our CRISPR/Cas9 screening may be useful in elucidating the molecular mechanism of OCCC tumorigenesis and in developing OCCC-targeted drugs.

The phosphate exporter XPR1/SLC53A1 is required for the tumorigenicity of epithelial ovarian cancer

Ovarian cancer is the fifth most common cause of cancer‐related death in women. Ovarian clear cell carcinoma (OCCC) is a chemotherapy‐resistant epithelial ovarian cancer with poor prognosis. As a basis for the development of therapeutic agents that could improve the prognosis of OCCC, we performed a screen for proteins critical for the tumorigenicity of OCCC using the CRISPR/Cas9 system. Here we show that knockdown of the phosphate exporter XPR1/SLC53A1 induces the growth arrest and apoptosis of OCCC cells in vitro. Moreover, we show that knockdown of XPR1/SLC53A1 inhibits the proliferation of OCCC cells xenografted into immunocompromised mice. These results suggest that XPR1/SLC53A1 plays a critical role in the tumorigenesis of OCCC cells. We speculate that XPR1/SLC53A1 might be a promising molecular target for the therapeutic treatment of OCCC.

Survival of Adolescents and Young Adults with Prevalent Poor-Prognosis Metastatic Cancers: A Population-Based Study of Contemporary Patterns and Their Implications

BACKGROUND

Although survival has improved dramatically for most adolescents and young adults (AYA; 15-39 years old) with cancer, it remains poor for those presenting with metastatic disease. To better characterize this subset, we conducted a landscape survival comparison with older adults (40-79 years).

METHODS

Using Surveillance, Epidemiology, and End Results Program data from 2000 to 2016, we examined incident cases of poor-prognosis metastatic cancers (5-year survival < 50%) among AYAs (n = 11,518) and older adults (n = 345,681) and compared cause-specific survival by sociodemographic characteristics (race/ethnicity, sex, and socioeconomic status). Adjusted HRs (aHR) for death from metastatic disease [95% confidence intervals (95% CI)] were compared between AYAs and older adults (Pint).

RESULTS

AYAs had significantly better survival than older adults for every cancer site except kidney, where it was equivalent (range of aHRs = 0.91; 95% CI, 0.82-1.02 for kidney cancer to aHR = 0.33; 95% CI, 0.26-0.42 for rhabdomyosarcoma). Compared with their older adult counterparts, greater survival disparities existed for AYAs who were non-Hispanic Black with uterine cancer (aHR = 2.20; 95% CI, 1.25-3.86 versus aHR = 1.40; 95% CI, 1.28-1.54; Pint = 0.049) and kidney cancer (aHR = 1.51; 95% CI, 1.15-1.98 versus aHR = 1.10; 95% CI, 1.03-1.17; Pint = 0.04); non-Hispanic Asian/Pacific Islanders with ovarian cancer (aHR = 1.47; 95% CI, 1.12-1.93 versus aHR = 0.89; 95% CI, 0.84-0.95; Pint<0.001); and males with colorectal cancer (aHR = 1.21; 95% CI, 1.10-1.32 versus aHR = 1.08; 95% CI, 1.06-1.10; Pint = 0.045).

CONCLUSIONS

AYAs diagnosed with these metastatic cancers have better survival than older adults, but outcomes remain dismal.

IMPACT

Overcoming the impact of metastasis in these cancers is necessary for continuing progress in AYA oncology. Sociodemographic disparities affecting AYAs within kidney, uterine, ovarian, and colorectal cancer could indicate plausible effects of biology, environment, and/or access and should be explored.

Incidence and predictive factors for recurrent clear cell ovarian carcinoma: results from a single center in Thailand

Objective

We aimed to study the incidence and predictive factors of recurrent clear cell ovarian carcinoma (CCC) and evaluate the oncological outcomes after recurrence.

Methods

This was a retrospective study of 134 CCC cases diagnosed between 2005 and 2020. Clinicopathological data and oncological outcomes were extracted and evaluated. Patients with co-malignancy, mixed pathological type, or incomplete data were excluded. Descriptive statistics, univariate and multivariable analyses, and Kaplan-Meier survival probability estimates were completed. A proportional hazards model was used to assess the association between the prognostic factors with progression-free survival (PFS), overall survival (OS), and post-recurrence survival.

Results

A total of 134 patients with CCC were enrolled. The incidence of recurrent CCC was 33.6% (45/134). The median PFS was 12.8 months (95% confidence interval [CI], 9.66–18.9) in the recurrence group and 3.3 months (95% CI, 1.15–4.4) in the refractory group. Residual tumor from surgical outcome, ascites cytology, and lymphovascular space invasion (LVSI) were independent prognostic factors for PFS. The significant variables were residual tumor (sub-optimal surgery vs. optimal surgery) (hazard ratio [HR], 2.68; 95% CI, 1.48–4.87; P=0.002), ascites cytology (positive vs. negative) (HR, 2.8; 95% CI, 1.58–4.98; P=0.002), and LVSI (positive vs. negative) (HR, 2.14; 95% CI, 1.18–3.86; P=0.04). The median post-recurrence survival was 13.96 months (95% CI, 10.61–26.2) in the recurrence group.

Conclusion

CCC has a high rate of recurrence. Sub-optimal surgery, positive ascites cytology, and LVSI indicated a worse prognosis for PFS. Optimal cytoreductive surgery is an important part of primary treatment to improve survival in patients with CCC.

Prognostic significance of the number of removed lymph nodes according to FIGO stage in ovarian clear cell carcinoma

A previous study by our group reported that removing a larger number of lymph nodes in patients with stage I ovarian clear cell carcinoma (OCCC) improved progression-free survival (PFS). The present study investigated whether clinical conditions, particularly the number of removed lymph nodes, are independent predictors of progression for stage II or higher OCCC and whether the significance of the number of removed lymph nodes differs according to FIGO stage for OCCC. A total of 113 patients with OCCC who had undergone surgery between January 1993 and December 2015 were retrospectively enrolled and the clinicopathological data were obtained from their medical records. Among patients with stage II or higher OCCC, PFS of those with no residual tumor or no lymph node metastasis was significantly better than that of those with residual tumor (P=0.023) or lymph node metastasis (P=0.035). Multivariate analysis revealed that no residual tumor was the only independent predictor for improved PFS of patients with stage II or higher. Regarding the number of removed lymph nodes, it did not significantly affect the PFS of patients with stage II or higher OCCC, whereas it improved the PFS of those with stage I, being an independent predictor of progression of stage I OCCC. In summary, although the number of removed lymph nodes was an independent predictor of progression for stage I OCCC, it was not for stage II or higher OCCC. The prognostic significance of the number of removed lymph nodes in OCCC may differ depending on the FIGO stage.

The post-progression survival of patients with recurrent or persistent ovarian clear cell carcinoma: results from a randomized phase III study in JGOG3017/GCIG

OBJECTIVE

In this study we sought to investigate the clinical factors that affect post-progression survival (PPS) in patients with recurrent or persistent clear cell carcinoma (CCC). We utilized the JGOG3017/Gynecological Cancer InterGroup data to compare paclitaxel plus carboplatin (TC) and irinotecan plus cisplatin (CPT-P) in the treatment of stages I to IV CCC.

METHODS

We enrolled 166 patients with recurrent or persistent CCC and assessed the impact of variables, including platinum sensitivity, treatment arm, crossover chemotherapy, primary stage, residual tumor at primary surgery, performance status, ethnicity, and tumor reduction surgery at recurrence on the median of PPS in patients with recurrent or persistent CCC.

RESULTS

A total of 77 patients received TC, and 89 patients received CPT-P. The median PPS for patients with platinum-resistant disease was 10.9 months, compared with 18.8 months for patients with platinum-sensitive disease (hazard ratio [HR]=1.88; 95% confidence interval [CI]=1.30-2.72; log-rank p<0.001). In the multivariate analysis, the platinum sensitivity (resistant vs. sensitivity; HR=1.60; p=0.027) and primary stage (p=0.009) were identified as independent predictors of prognosis factors for PPS in recurrent or persistent CCC.

CONCLUSIONS

Our findings revealed that platinum sensitivity and primary stage are clinical factors that significantly affect PPS in patients with recurrent or persistent CCC as well as other histologic subtypes of ovarian cancer. PPS in patients with recurrent CCC should establish the basis for future clinical trials in this population.

A CLEARER VIEW ON OVARIAN CLEAR CELL CARCINOMA

Introduction: Ovarian clear cell carcinoma (OCCC) is a less common subtype accounting for approximately 5% of all epithelial ovarian cancers (EOCs). Clinical experience and research findings confirm the remarkable differences in clinical behavior, molecular alterations and pathogenesis of OCCC. The diagnosis of OCCC is typically set at a younger age, and earlier stage and in a background of endometriosis.Results: Molecularly, OCCCs rarely harbor BRCA1/BRCA2 mutations and have fewer copy number variants (CNVs). The most common molecular changes occur in the SWI/SNF chromatin remodeling complex genes, the PI3K/AKT signaling pathway and the receptor tyrosine kinase (RTK)/Ras signaling pathway.Five-year disease-specific survival of patients with OCCC is worse compared to high grade serous carcinomas (HGSOC). The current treatment options for OCCC are based on studies that included patients with predominantly HGSOC and only a minor proportion of cancers with clear cell histology. In order to improve outcomes for patients with OCCC, research should be specific for this subtype.Discussion: As the available information about the specific characteristics of OCCC is increasing, especially at a molecular level, it should be possible to continuously improve the specific diagnostics and treatment. Since OCCC is so rare, it is essential to collect new evidence at an international level. To avoid extrapolation from EOC trials with possible erroneous conclusions, patients should always be encouraged to participate in specific histological trials and basket trials, while paying extra attention to OCCC-like subtypes.

Clear cell carcinoma of the ovary: Epidemiology, pathological and biological features, treatment options and clinical outcomes

Clear cell carcinoma of the ovary is a rare and distinct histotype of epithelial ovarian carcinomas. Women diagnosed with clear cell carcinomas are usually younger and diagnosed at earlier stages than those with the most common high-grade serous histology. Endometriosis is considered a main risk factor for the development of clear cell carcinoma of the ovary, and it can be considered a precursor of of this tumor, as it is identified in more than 50% of patients with clear cell carcinoma. Different molecular pathways and alterations heve been identified in ovarian clear cell carcinoma, including the most common mutations of AT-rich interaction domain 1A [ARID1A] and phosphatidylinositol-4,5-bisphosphate 3-kinase [PIK3] catalytic subunit alpha [PIK3CA]. The prognosis of patients at early stage is favorable, while patients with advanced or recurrent disease experience a poor oncologic outcomes. Despite a lower rate of responses due to an intrinsic chemoresistance, the treatment strategy for advanced disease resembles the treatment of high-grade serous carcinoma, which includes aggressive cytoreductive surgery and platinum-based chemotherapy. For this reason, the role of adjuvant chemotherapy in patients with stage I disease undergoing complete surgical staging is still under debate. Alternative treatments, including biological agents that target different pathways constitute the most promising treatment strategies, and well-designed, collaborative international trials should be designed in order to improve the oncologic outcomes and the quality of life of patients with this aggressive disease.

Bevacizumab in First-Line Chemotherapy Improves Progression-Free Survival for Advanced Ovarian Clear Cell Carcinoma

Simple Summary

We investigated survival outcomes following first-line chemotherapy before and after approval of bevacizumab for ovarian cancer in Japan to evaluate the efficacy of bevacizumab for advanced clear cell carcinoma. We investigated 28 consecutive patients diagnosed with clear cell carcinoma (stages III/IV) at our hospital between 2008 and 2018. Bevacizumab was administered for treatment after approval in Japan in November 2013. Progression-free survival was compared between 10 patients treated before bevacizumab approval (2008–2013,) and 18 patients treated after Bev approval (2014–2018) for first-line chemotherapy. The median progression-free survival increased from 12.0 months before bevacizumab approval to 29.8 months after bevacizumab approval (Wilcoxon test, p = 0.026). Multivariate analysis showed that performance status (p = 0.049), bevacizumab administration (p = 0.023) and completeness of resection (p = 0.023) were independent prognostic factors for progression-free survival. Bevacizumab incorporated into first-line chemotherapy might improve progression-free survival in patients with advanced clear cell carcinoma.

Abstract

(1) Background: We investigated survival outcomes following first-line chemotherapy before and after approval of bevacizumab (Bev) for ovarian cancer in Japan to evaluate the efficacy of Bev for advanced clear cell carcinoma (CCC). (2) Methods: We investigated 28 consecutive patients diagnosed with CCC (stages III/IV) at our hospital between 2008 and 2018. Bev was administered for treatment of advanced CCC after approval in Japan in November 2013. Progression-free survival (PFS) was compared between 10 patients treated before Bev approval (2008–2013, Bev- group) and 18 patients treated after Bev approval (2014–2018, Bev+ group) for first-line chemotherapy. (3) Results: No intergroup difference was observed in patient characteristics. The rate of completeness of resection was higher in the Bev − group (9/10, 90%) than in the Bev+ group (15/18, 83%) (p = 0.044). Eleven (61%) patients in the Bev + group received ≥ 21 cycles of Bev. The median PFS increased from 12.0 months before Bev approval to 29.8 months after Bev approval (Wilcoxon test, p = 0.026). Multivariate analysis showed that performance status (p = 0.049), Bev administration (p = 0.023) and completeness of resection (p = 0.023) were independent prognostic factors for PFS. (4) Conclusions: Bev incorporated into first-line chemotherapy might improve PFS in patients with advanced CCC. We hope that our findings will be confirmed in adequate clinical trials.

Clear cell carcinoma of the ovary: a clinical and molecular perspective

Clear cell carcinoma of the ovary has distinct biology and clinical behavior. There are significant geographical and racial differences in the incidence of clear cell carcinoma compared with other epithelial ovarian tumors. Patients with clear cell carcinoma are younger, tend to present at an early stage, and their tumors are commonly associated with endometriosis, which is widely accepted as a direct precursor of clear cell carcinoma and has been identified pathologically in approximately 50% of clear cell carcinoma cases. The most frequent and important specific gene alterations in clear cell carcinoma are mutations of AT-rich interaction domain 1A (ARID1A) (~50% of cases) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) (~50% cases). More broadly, subgroups of clear cell carcinoma have been identified based on C-APOBEC (apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like) and C-AGE (age-related) mutational signatures. Gene expression profiling shows upregulation of hepatocyte nuclear factor 1-beta (HNF1β) and oxidative stress-related genes, and has identified epithelial-like and mesenchymal-like tumor subgroups. Although the benefit of platinum-based chemotherapy is not clearly defined it remains the mainstay of first-line therapy. Patients with early-stage disease have a favorable clinical outcome but the prognosis of patients with advanced-stage or recurrent disease is poor. Alternative treatment strategies are required to improve patient outcome and the development of targeted therapies based on molecular characteristics is a promising approach. Improved specificity of the histological definition of this tumor type is helping these efforts but, due to the rarity of clear cell carcinoma, international collaboration will be essential to design appropriately powered, large-scale clinical trials.

Diagnostic efficacy of ascites cell block for ovarian clear cell carcinoma

BACKGROUND

Ascites cytology is important for determining the stage and treatment methods for ovarian clear cell carcinoma (CCC) as defined by the 2014 International Federation of Obstetrics and Gynecology classification.

METHODS

Patients with CCC who underwent surgery at our hospital between January 2012 and December 2019 and who received cytodiagnosis of their ascites using Papanicolaou (Pap) and May-Grünwald-Giemsa (MGG) staining, and cell block methods were identified. The cell block technique was performed using hematoxylin-eosin (H&E) staining and immunohistochemical staining for hepatocyte nuclear factor-1β (HNF-1β), estrogen receptor (ER), progesterone receptor (PR), and Wilms tumor-1 (WT-1). Cancer cells of CCC were defined as tumor cells that were positive for HNF-1β and negative for ER, PR, and WT-1. The diagnostic accuracy of ascites cytology using Pap and MGG staining and cell block methods was examined.

RESULTS

Based on cytological data, our study included 17 patients: seven (41.1%) with malignant (MAL) ascites, eight (47.1%) with negative for malignancy (NFM), and two (11.8%) with atypia of undetermined significance (AUS) because of a few atypical cells based on Pap and MGG staining. Malignant cells diagnosed by cell blocks were detected in 7/7 patients with MAL ascites based on PAP and MGG staining, 2/8 (25.0%) patients with NFM, and 1/2 (50%) patients with AUS.

CONCLUSION

These findings show that the cell block method combined with the immunohistochemical investigation may be useful for increasing the diagnostic accuracy of malignant cells in CCC.

Residual Tumor Diameter Predicts Progression After Primary Debulking Surgery of Ovarian Clear Cell Carcinoma (OCCC): Clinicopathologic Study of Stage II-IV OCCC Patients from a Single Institution

Introduction

Ovarian clear cell carcinoma (OCCC) is a subtype of ovarian cancer characterized by highly aggressive and poor prognosis. However, it is unclear what factors are associated with OCCC recurrence and death. The study aimed to evaluate whether residual tumor diameter after primary debulking surgery, or other clinicopathological features play roles in predicting survival outcome in stage II–IV OCCC patients.

Material and Methods

We present a retrospective study of OCCC patients with stage II–IV in our department from 2010 to 2015. Kaplan–Meier method was used to draw a survival curve. Survival analysis was performed using Log-rank test for univariate analysis and COX proportional risk regression model for multivariate analysis.

Results

In this cohort of 78 patients who underwent primary debulking surgery, 47 patients had disease recurrence and 32 cases died. On univariate analysis, FIGO stage, residual tumor diameter and ascites were significant predictors of 3-year PFS (P values<0.05) and OS (P values<0.05). On multivariate analysis, the residual tumor diameter was an independent prognostic factor for 3-year PFS and OS (P values<0.05). The outcomes of patients in residual-free group were significantly better than those in the residual tumor diameter 0–1cm and >1cm group (PFS: P=0.000, OS: P=0.001), but there was no significant difference in prognosis between 0–1cm and > 1cm group (P values >0.05). Greater residual tumor diameter predicted progression on cox analysis in patients with stage III, but not for patients with stage IV.

Conclusion

Residual tumor diameter is prognostic after surgery for OCCC. Achieving no residual disease will significantly improve the prognosis in advanced OCCC patients.

Updates of Pathogenesis, Diagnostic and Therapeutic Perspectives for Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is a special pathological type of epithelial ovarian carcinoma (EOC) and has a high prevalence in Asia without specific molecular subtype classification. Endometriosis is a recognized precancerous lesion that carries 3-fold increased risk of OCCC. Ovarian endometrioid carcinoma, which also originates from endometriosis, shares several features with OCCC, including platinum resistance and younger age at diagnosis. Patients with OCCC have about a 2.5 to 4 times greater risk of having a venous thromboembolism (VTE) compared with other EOC, and OCCC tends to metastasize through lymphatic vesicular and peritoneal spread as opposed to hematogenous metastasis. There is only mild elevation of the conventional biomarker CA125. Staging surgery or optimal cytoreduction combined with chemotherapy is a common therapeutic strategy for OCCC. However, platinum resistance commonly portends a poor prognosis, so novel treatments are urgently needed. Targeted therapy and immunotherapy are currently being studied, including PARP, EZH2, and ATR inhibitors combined with the synthetic lethality of ARID1A-dificiency, and MAPK/PI3K/HER2, VEGF/bFGF/PDGF, HNF1β, and PD-1/PD-L1 inhibitors. Advanced stage, suboptimal cytoreduction, platinum resistance, lymph node metastasis, and VTE are major prognostic predictors for OCCC. We focus on update pathogenesis, diagnostic methods and therapeutic approaches to provide future directions for clinical diagnosis and treatment of OCCC.

Clinical characteristics and prognostic factors of stage IC ovarian clear cell carcinoma: a Surveillance, Epidemiology, and End Results (SEER) analysis

PURPOSE

The study aimed to investigate the clinical characteristics and prognostic factors of stage IC ovarian clear cell carcinoma (OCCC).

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was accessed for medical records of patients with stage IC OCCC from 1992 to 2016. The clinical and prognostic features of stage IC OCCC from several therapeutic perspectives were identified with Kaplan-Meier method and Cox proportional hazards model.

RESULTS

Totally, 1079 patients were enrolled for the analysis. The median age was 55 (range 24-91) years. 850 (78.8%) patients were treated with chemotherapy, 877 (81.3%) received lymph node (LN) dissection, and 20 (1.9%) underwent radiotherapy. LN dissection (P = 0.501) and chemotherapy (P = 0.130) did not significantly impact cancer-specific survival (CSS). Among patients younger than 45 years, 23 received fertility-sparing surgery (FSS). No significant difference in CSS was observed between the FSS and non-FSS group (P = 0.523). Bilateral tumor (P < 0.001) and larger tumor size (P = 0.010) were significantly and independently associated with poor CSS. Older age (P = 0.001), bilateral tumor (P < 0.001), and larger tumor size (P = 0.005) were significantly and independently associated with poor overall survival (OS), while LN dissection (P = 0.005) was significantly and independently associated with better OS. Significant differences in CSS (P = 0.005) and OS (P < 0.001) were observed between the low- and high-risk groups, which were divided by median risk score.

CONCLUSION

LN dissection and chemotherapy did not significantly impact CSS, while LN dissection was an independent prognostic factor for OS. Convincing evidence from clinical trials with a large number of patients are further required to develop treatment guidelines.

Effects of activating GABAB1 receptor on proliferation, migration, invasion and epithelial-mesenchymal transition of ovarian cancer cells

OBJECTIVE

This study aimed to explore the effects of activating GABAB1 receptor by baclofen on proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of ovarian cancer cells.

RESULTS

One hundred μmol/L, 200 μmol/L and 300 μmol/L were selected as low, medium and high baclofen concentrations respectively. Cells were divided into four groups: Control, 100 μmol/L, 200 μmol/L and 300 μmol/L. Compared with the control group, the viability, colony formation, migration and invasion of SKOV3 cells were inhibited, and the apoptosis of SKOV3 cells were enhanced significantly at 200 μmol/L and 300 μmol/L baclofen. Moreover, they changed significantly with the increase of baclofen concentration. Compared with the control group, the expression of E-cadherin and GABAB1 increased and the N-cadherin expression decreased significantly in 200 μmol/L and 300 μmol/L groups. Higher concentration of baclofen induced higher expression of E-cadherin and lower expression of N-cadherin.

CONCLUSION

Baclofen inhibited the proliferation, cloning, migration, invasion and EMT of ovarian cancer cells by activating GABAB1 receptor. These results might contribute a lot to clarify the role and possible mechanism of GABAB1 receptor in ovarian cancer.

Early-stage clear cell ovarian cancer compared to high-grade histological subtypes: An outcome exploratory analysis in two oncology centers

OBJECTIVE

advanced stage clear cell ovarian cancer (CCOC) carries a higher risk of relapse and death compared to other histological subtypes. The prognosis of early-stage CCOC is controversial.

METHODS

Early-stage high-grade OC patients from two Italian oncologic centers were included. Patients with early-stage CCOC were compared with those with high-grade endometrioid (HGE) and serous (HGS) OC in terms of relapse-free interval (RFI), cancer-specific survival (CSS) and post relapse cancer-specific survival (prCSS). The Cox proportional hazard model and the restricted mean survival time were used.

RESULTS

Between 1981 and 2012, 134 patients with CC, 152 with HGE and 160 with HGS were treated at two referral centers. Median follow-up was 11.5 years. Ten years RFI rates were 80.6%, 72.1%, 60.6%, and CSS rates were 84.3%, 82.6%, 81.7% respectively. Adjuvant chemotherapy significantly improved RFI (aHR 0.61, 95%CI 0.40 to 0.91, P = 0.015). In the multivariable analysis HGS histotype was associated with a shorter RFI compared to CC, (Hazard Ratio [HR]: 1.81; 95%CI: 1.12-2.93; P = 0.016), whereas CSS was not statistically different. prCSS was longer in HGS compared to CCOC (HR, 0.36; 95% CI, 0.17-0.74; P = 0.006). According to the stage, IA/IB/IC1 HGSOC had a shorter RFI (HR, 2.13; 95% CI, 1.14-3.99; P = 0.018) compared to IA/IB/IC1 CCOC, but similar CSS. For prCSS, CC compared to HGS conferred a worse prognosis regardless of the initial stage.

CONCLUSIONS

Early-stage CCOC is associated with a longer RFI, similar CSS and a shorter prCSS compared to HGSOC. No prognostic differences were observed between CC and HGE OC. The relapse risk was the lowest in IA/IB/IC1 CC compared to HGS, whereas CC displayed poor sensitivity to chemotherapy after relapse.

Adjuvant Treatment of Early Ovarian Clear Cell Carcinoma: A Population-Based Study of Whole Abdominal Versus Pelvic Nodal Radiotherapy

BACKGROUND

Adjuvant treatment in early ovarian clear cell carcinoma (OCCC) is not yet standardized. The objective of this population-based study was to compare the outcome of patients with early OCCC treated with adjuvant chemotherapy versus chemoradiotherapy (chemoRT) and evaluate the association of adjuvant radiotherapy regimens (whole abdominal radiotherapy [WART] versus pelvic nodal radiotherapy [PRT]) with outcome.

PATIENTS AND METHODS

Chart review was conducted to identify patients with stage I and II OCCC with complete information on staging. Patients with stage IA, IB, or IC OCCC purely resulting from capsular rupture were excluded because the provincial protocol does not recommend adjuvant treatment.

RESULTS

Overall, 403 patients were identified and 343 received adjuvant treatment, of whom 255 had stage IC or II OCCC and 153 were eligible for final analysis. On Cox multivariable regression, receipt of chemoRT (n=90) was associated with an improvement in failure-free survival (FFS) (hazard ratio [HR], 0.57; 95% CI, 0.34-0.94) compared with chemotherapy alone (n=63). Use of chemoRT also resulted in 54% reduction in the cumulative incidence of cancer-specific mortality (subdistribution HR, 0.46; 95% CI, 0.24-0.89). However, there was no significant difference in the HR for overall survival (OS) between the chemoRT (HR, 0.70; 95% CI, 0.43-1.13) and chemotherapy group. Relative to chemotherapy + WART (chemo-WART), chemotherapy + PRT (chemo-PRT) was not associated with any significant difference in HR for FFS (HR, 1.34; 95% CI, 0.40-4.44) or OS (HR, 1.13; 95% CI, 0.37-3.46).

CONCLUSIONS

Adjuvant chemoRT was associated with a lower risk of failure compared with chemotherapy alone. However, there was no difference in OS between the adjuvant chemotherapy and chemoRT regimens. Additionally, no significant difference in terms of FFS or OS was found between the chemo-WART and chemo-PRT groups.

Targeting an autocrine IL-6-SPINK1 signaling axis to suppress metastatic spread in ovarian clear cell carcinoma

A major clinical challenge of ovarian cancer is the development of malignant ascites accompanied by widespread peritoneal metastasis. In ovarian clear cell carcinoma (OCCC), a challenging subtype of ovarian cancer, this problem is compounded by near-universal primary chemoresistance; patients with advanced stage OCCC thus lack effective therapies and face extremely poor survival rates. Here we show that tumor cell expressed serine protease inhibitor Kazal type 1 (SPINK1) is a key driver of OCCC progression and metastasis. Using cell culture models of human OCCC, we find that shRNA silencing of SPINK1 sensitizes tumor cells to anoikis and inhibits proliferation. Knockdown of SPINK1 in OCCC cells also profoundly suppresses peritoneal metastasis in mouse implantation models of human OCCC. We next identify a novel autocrine signaling axis in OCCC cells whereby tumor cell-produced interleukin-6 (IL-6) regulates SPINK1 expression to stimulate a common protumorigenic gene expression pattern leading to anoikis resistance and proliferation of OCCC cells. We further demonstrate that this signaling pathway can be successfully interrupted with the IL-6Rα inhibitor tocilizumab, sensitizing cells to anoikis in vitro and reducing metastasis in vivo. These results suggest that clinical trials of IL-6 pathway inhibitors in OCCC may be warranted, and that SPINK1 might offer a candidate predictive biomarker in this population.

Effect of murine double-minute 2 inhibitors in preclinical models of advanced clear cell carcinomas originating from ovaries and kidneys

Advanced clear cell carcinomas originating from both ovaries and kidneys with cancerous peritonitis have poor prognoses. Murine double-minute 2 (MDM2) is a potential therapeutic target for clear cell ovarian carcinomas with WT TP53. Herein, we characterized the antiangiogenic and antitumor effects of the MDM2 inhibitors DS-3032b and DS-5272 in 6 clear cell ovarian carcinoma cell lines and 2 clear cell renal carcinoma cell lines, as well as in clear cell ovarian carcinomas s.c. xenograft and ID8 (murine ovarian cancer cells with WT TP53) cancer peritonitis mouse models. In clear cell ovarian carcinoma s.c. xenograft mouse models, DS-3032b significantly reduced WT TP53 clear cell ovarian carcinoma- and clear cell renal carcinoma-derived tumor volumes. In ID8 mouse models, DS-5272 significantly inhibited ascites production, reduced body weight, and significantly improved overall survival. Additionally, DS-5272 reduced the tumor burden of peritoneal dissemination and decreased CD31⁺ cells in a dose-dependent manner. Furthermore, DS-5272 significantly decreased vascular endothelial growth factor concentrations in both sera and ascites. Combined therapy with MDM2 inhibitors and everolimus showed synergistic, and dose-reduction potential, for clear cell carcinoma treatment. Our findings suggest that MDM2 inhibitors represent promising molecular targeted therapy for clear cell carcinomas, thereby warranting further studies to evaluate the efficacy and safety of dual MDM2/mTOR inhibitors in clear cell carcinoma patients.

Genomic characterization of Chinese ovarian clear cell carcinoma identifies driver genes by whole exome sequencing

Little is known about the genetic alterations characteristic of ovarian clear cell carcinoma (OCCC). Our aim was to identify targetable genomic alterations in this type of cancer. Forty-two OCCC formalin-fixed, paraffin-embedded (FFPE) tissue samples were analyzed by whole-exome sequencing (WES), and 74 FFPE tissue samples underwent targeted sequencing (TS) to confirm the relevant driver mutations. Cell proliferation was assessed by cell counting kit-8 (CCK8) assays. In the 42 samples, ARID1A (64.3%) and PIK3CA (28.5%) were frequently mutated, as were PPP2R1A (11.9%), PTEN (7.1%) and KRAS (4.8%), which have been reported in previous OCCC studies. We also detected mutations in MUC4 (28.6%), MAGEE1 (19%), and ARID3A (16.7%); associations with these genes have not been previously reported. The functional protein-activated pathways were associated with proliferation and survival (including the PI3K/AKT, TP53, and ERBB2 pathways) in 83% of OCCCs and with chromatin remodeling in 71% of OCCCs. Patients with alterations in MAGEE1 (64% in the targeted sequencing cohort) had worse clinical outcomes (log-rank p < 0.05). A functional study revealed that two MAGEE1 mutants, one lacking two MAGE domains and the other containing two MAGE domains, significantly decreased the proliferative capacity of OCCC cells. We successfully identified novel genetic alterations in OCCC using whole-exome sequencing and targeted sequencing of OCCC patient samples and potential therapeutic targets for the treatment of this malignancy.

Prognostic factors and effects of fertility-sparing surgery in women of reproductive age with ovarian clear-cell carcinoma: a propensity score analysis

Objective

The aim of this study was to investigate the clinical characteristics of young patients with stage I clear-cell carcinoma (CCC) and evaluate the prognostic factors and effects of fertility-sparing surgery (FSS) using propensity score (PS) adjustment.

Methods

We conducted a regional multi-institutional study between 1986 and 2017. Among 4,277 patients with ovarian tumor, clinical and pathological data of 103 fertile women with stage I unilateral CCC were collected. We evaluated survival and reproductive outcomes in these patients. Additionally, to analyze the effects of FSS, baseline imbalance between patients with and those without FSS was adjusted with an inverse probability of treatment weighting using PSs involving independent clinical variables.

Results

The mean patient age was 39.4 years, and the median follow-up period for surviving patients was 55.6 months. In multivariate analysis, stage IC2/IC3 (vs. IA/IC1) was the only independent prognostic factor for recurrence-free survival (RFS) and overall survival (OS). FSS was not associated with poorer prognosis when compared to the prognosis with non-preserving surgery with regard to both RFS and OS. No statistical difference in survival outcomes between FSS and other approaches was confirmed after PS adjustment. Among patients who underwent FSS, four deliveries with healthy neonates were noted without any gestational complications.

Conclusion

FSS can be considered in stage I CCC, specifically in stage IA and IC1 patients who strongly desire to have children in the future. Further clinical research is needed to clarify the optimal application of FSS for CCC.

Apparent diffusion coefficient (ADC) values of serous, endometrioid, and clear cell carcinoma of the ovary: pathological correlation

BACKGROUND

Primary epithelial ovarian cancer is divided into several subtypes. The relationships between apparent diffusion coefficient (ADC) values and their subtypes have not yet been established.

PURPOSE

To investigate whether ADC values of epithelial ovarian cancer vary according to histologic tumor cellularity and evaluate the difference of clear cell carcinoma (CCC), high-grade serous carcinoma (HGSC), and endometrioid carcinoma (EC).

MATERIAL AND METHODS

This retrospective study included 51 cases of epithelial ovarian cancer (17 CCC, 20 HGSC, and 14 EC) identified by magnetic resonance imaging with pathological confirmation. All patients underwent diffusion-weighted imaging and the ADC values of lesions were measured. We counted the tumor cells in three high-power fields and calculated the average for each case. The Spearman's correlation coefficient test was used to analyze correlation between ADC values and tumor cellularity. The ADC values of HGSC, EC, and CCC were compared using the Steel-Dwass test.

RESULTS

The ADC values of all cases were significantly inversely correlated with tumor cellularity (r_s = -0.761; P < 0.001). The mean ± SD ADC values (×10^-3 mm²/s) of CCC, HGSC, and EC were 1.24 ± 0.17 (range 0.98--1.65), 0.84 ± 0.10 (range 0.67--1.06), and 0.84 ± 0.10 (range 0.67--1.07). The mean ± SD tumor cellularity of CCC, HGSC, and EC was 162.88 ± 63.28 (range 90.33--305.67), 440.60 ± 119.86 (range 204.67--655.67), and 461.02 ± 81.86 (range 333.33--602.33).

CONCLUSION

There is a significant inverse correlation between ADC values and tumor cellularity in epithelial ovarian cancer. The mean ADC value of CCC was higher than those of HGSC and EC, seemingly due to the low cellularity of CCC.

Current and future strategies for treatment of ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC) is one of the five histological types of epithelial ovarian cancer (EOC). OCCC comprises 23% of all EOC cases in Japan, whereas the rate of OCCC in North America and Europe is much lower. OCCC is generally categorized as a rare gynecologic malignancy, and there is limited evidence for specific treatment. The clinical basis for treatment of OCCC is mostly based on retrospective studies, many of which were performed in Japan. Until recently, most randomized clinical trials for EOC have included OCCC; therefore, current treatment for OCCC is basically the same as that for other histologic types of EOC. However, the clinical characteristics of OCCC differ from those of high-grade serous carcinoma, particularly for chemosensitivity, and there is a need to develop new treatment for OCCC. The molecular background of OCCC has unique features: tumors are usually negative for p53 mutations and positive for ARID1A and/or PIK3CA mutations, whereas p53 mutations are common in high-grade serous or endometrioid carcinomas. These features may help in development of new treatment for OCCC. In this review, we described the current evidence for treatment of OCCC, including surgery, radiotherapy, chemotherapy, molecular targeted therapy and immunotherapy, and we discuss ongoing clinical trials and preclinical studies of new treatment approaches for OCCC.