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

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.

Shifting incidence and survival of epithelial ovarian cancer (1995-2014): A SurvMark-2 study

The aim of the study is to provide a comprehensive assessment of incidence and survival trends of epithelial ovarian cancer (EOC) by histological subtype across seven high income countries (Australia, Canada, Denmark, Ireland, New Zealand, Norway and the United Kingdom). Data on invasive EOC diagnosed in women aged 15 to 99 years during 1995 to 2014 were obtained from 20 cancer registries. Age standardized incidence rates and average annual percentage change were calculated by subtype for all ages and age groups (15-64 and 65-99 years). Net survival (NS) was estimated by subtype, age group and 5-year period using Pohar-Perme estimator. Our findings showed marked increase in serous carcinoma incidence was observed between 1995 and 2014 among women aged 65 to 99 years with average annual increase ranging between 2.2% and 5.8%. We documented a marked decrease in the incidence of adenocarcinoma "not otherwise specified" with estimates ranging between 4.4% and 7.4% in women aged 15 to 64 years and between 2.0% and 3.7% among the older age group. Improved survival, combining all EOC subtypes, was observed for all ages combined over the 20-year study period in all countries with 5-year NS absolute percent change ranging between 5.0 in Canada and 12.6 in Denmark. Several factors such as changes in guidelines and advancement in diagnostic tools may potentially influence the observed shift in histological subtypes and temporal trends. Progress in clinical management and treatment over the past decades potentially plays a role in the observed improvements in EOC survival.

Endometriosis-Related Ovarian Cancers: Evidence for a Dichotomy in the Histogenesis of the Two Associated Histotypes

Evidence indicates that different pathways of malignant degeneration underlie the development of endometriosis-associated ovarian tumors of endometrioid and clear cell histotypes. The aim of this study was to compare data from patients affected by these two histotypes to investigate the hypothesis of a dichotomy in the histogenesis of these tumors. Clinical data and tumor characteristics of 48 patients who were diagnosed with either pure clear cell ovarian cancer and mixed endometrioid-clear cell ovarian cancer arising from endometriosis (ECC, n = 22) or endometriosis-associated endometrioid ovarian cancer (EAEOC, n = 26) were compared. A previous diagnosis of endometriosis was detected more frequently in the ECC group (32% vs. 4%, p = 0.01). The incidence of bilaterality was significantly higher in the EAOEC group (35% vs. 5%, p = 0.01) as well as a solid/cystic rate at gross pathology (57.7 ± 7.9% vs. 30.9 ± 7.5%, p = 0.02). Patients with ECC had a more advanced disease stage (41% vs. 15%; p = 0.04). A synchronous endometrial carcinoma was detected in 38% of EAEOC patients. A comparison of the International Federation of Gynecology and Obstetrics (FIGO) stage at diagnosis showed a significantly decreasing trend for ECC compared to EAEOC (p = 0.02). These findings support the hypothesis that the origin, clinical behavior and relationship with endometriosis might be different for these histotypes. ECC, unlike EAEOC, seems to develop within an endometriotic cyst, thus representing a window of possibility for ultrasound-based early diagnosis.

The Significance of Radiotherapy in Ovarian Clear Cell Carcinoma: A Systematic Review and Meta-Analysis

OBJECTIVE

To assess the response rate and survival effect of adjuvant radiotherapy (RT) or chemoradiotherapy (CRT) during ovarian clear cell carcinoma (OCCC).

METHODS

We searched Web of Science, PubMed, Cochrane library electronic databases, Clinical Trials, WanFang Data and Chinese National Knowledge Infrastructure (CNKI) up to October 2022. We also searched registers of clinical trials, abstracts of scientific meetings and reference lists of included studies.

RESULTS

We identified a total of 4259 patients from 14 studies met the inclusion criteria. The pooled response rate of residual tumors for RT/CRT was 80.0%, the pooled 5-year progression-free survival (PFS) ratio during RT/CRT group was 61.0%, and the pooled 5-year overall survival (OS) ratio during RT/CRT group was 68.0%; heterogeneity tests demonstrated significant difference between studies (I² >50%). Cumulative results suggested adjuvant RT/CRT improved 5-year PFS ratio of OCCC patients (OR: 0.51 (95% CI: 0.42-.88), I² = 22%, P = .009), had no impact on 5-year OS ratio (OR: 0.52 (95% CI: 0.19-1.44), I² = 87%, P = .21); meta-regression of studies before and after 2000 found consistent results. Sub-analysis observed that adjuvant RT/CRT had no impact on 5-year OS ratio of early-stage (stage I + II) OCCC patients (OR: 0.67 (95% CI: 0.25-1.83), I² = 85%, P = .44), but might improve 5-year OS ratio of advanced and recurrent OCCC patients (OR: 0.13(95% CI: 0.04-.44), P = .001).

CONCLUSION

This analysis suggested that adjuvant RT/CRT might improve oncologic outcomes of OCCC, especially for advanced and recurrent cases. Due to the inherent selective biases of retrospective studies enrolled in the meta-analysis, more convincing evidences based on prospective randomized controlled trials (RCTs) are urgently needed.

Patients with stage IA ovarian clear cell carcinoma do not require chemotherapy following surgery

BACKGROUND

Ovarian clear cell carcinoma (OCCC) is an infrequent histological subtype of epithelial ovarian cancer (EOC). The present study aimed to investigate whether chemotherapy is indispensable for patients with stage IA OCCC.

METHODS

Data were collected from the Surveillance, Epidemiology and End Results database between 2004 and 2015. All subjects were diagnosed with stage IA OCCC, according to their postoperative pathological reports. In the present study, 1038 patients were retrospectively investigated, among whom 692 patients received chemotherapy. Propensity score matching (PSM) was performed to prevent selection bias. The multivariate Cox proportional hazards model was used to analyze the correlation between variables and 5-year overall survival.

RESULTS

An equal number of patients (n = 346) who did or did not undergo chemotherapy after PSM were further enrolled in the study. The results showed that the mortality of OCCC increased for the patients aged ≥50 years. In addition, older age was associated with lower 5-year overall survival (p < 0.05). However, chemotherapy did not extend the 5-year overall survival (p = 0.524) of patients with stage IA OCCC, according to the multivariate Cox regression analysis.

CONCLUSIONS

Chemotherapy did not affect the overall survival of patients with stage IA OCCC following surgery.

Primary Laparoscopic Surgery Does Not Affect the Prognosis of Early-Stage Ovarian Clear Cell Cancer

Purpose

Minimally invasive surgery (MIS) is performed frequently in early-stage ovarian cancer patients, especially in ovarian clear cell carcinoma (OCCC). The aim of this study was to investigate whether primary laparoscopic surgery influences prognosis in patients with early-stage OCCC.

Patients and Methods

Patients with International Federation of Gynecology and Obstetrics (FIGO) stage I  OCCC were retrospectively reviewed in two hospitals between April 2010 and August 2020. Clinical data were abstracted, and patients were followed up until February 2021. Patients were divided into open surgery (laparotomy) and laparoscopy groups, and the Kaplan–Meier method was applied to compare progression-free survival (PFS) and overall survival (OS) between the groups. Statistical differences were determined by the Log rank test.

Results

Eighty-nine patients were included in the study; 20 (22.5%) and 69 (77.5%) patients underwent laparoscopic and open surgery, respectively. The patients’ characteristics were well-balanced except that patients in the laparoscopy group tended to have smaller tumors and lower frequency of omentectomy and lymphadenectomy compared with the open surgery group. The median follow-up duration was 42.6 and 36.5 months in the laparoscopy and open surgery groups, respectively. Nine (10.1%) patients developed recurrence, and 4 (4.5%) died of the disease; all in the open surgery group. The estimated 2-year PFS rates were 100.0% and 90.1%, and the estimated 5-year OS rates were 100.0% and 91.9% in the laparoscopy and open surgery groups, respectively. No significant survival differences were found between the groups.

Conclusion

Survival was not compromised when primary laparoscopic surgery was performed in early-stage OCCC patients. A well-designed randomized controlled trial is warranted.