# Clear cell ovarian cancer

Source: https://onco.cc/cancers/clear-cell-ovarian-cancer/  
OnCo record `clear-cell-ovarian-cancer` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Clear cell ovarian cancer grows out of endometriosis, is usually caught early and cured by surgery, but when advanced it resists platinum chemotherapy. Its distinct genetics, with ARID1A and PIK3CA mutations, are the focus of targeted and immune approaches.

## Summary

Clear cell carcinoma is strongly associated with endometriosis and is commoner in East Asian women. About half carry ARID1A mutations and a third PIK3CA mutations; TP53 is usually wild-type. It presents as a large unilateral mass, often at stage I, with a raised risk of venous thromboembolism and hypercalcaemia. Surgery is curative for most early disease, with adjuvant carboplatin-paclitaxel for stage IC and above; advanced and recurrent disease respond poorly to chemotherapy and do not benefit from PARP inhibitors. Immune checkpoint inhibitors have produced responses in a minority, and trials target ARID1A loss (ATR and EZH2 inhibitors), PI3K and the hypoxia pathway.

## Fields

- Kind: Cancer
- Last checked: 2026-09-17
- Also known as: Ovarian clear cell carcinoma; OCCC
- Tags: subtype-page
- Group: gynaecologic
- Burden: About one in ten ovarian cancers in Western countries and a quarter in Japan; most present at an early stage and are cured, but advanced disease responds poorly to chemotherapy and carries a worse outlook than high-grade serous cancer.
- Subtypes: Clear cell carcinoma arising in endometriosis; Stage I clear cell carcinoma (most cases); Advanced and recurrent clear cell carcinoma (chemoresistant)
- Biomarkers: ARID1A mutation (about 50 percent); PIK3CA mutation; HNF1B expression (diagnostic); Mismatch repair deficiency (a minority); Wild-type TP53

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/clear-cell-ovarian-cancer/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/clear-cell-ovarian-cancer/#overview [3 state-of-the-art points]
- Types and stages (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/clear-cell-ovarian-cancer/#what-it-is [3 subtypes]
- Symptoms and diagnosis (on the hub): How this cancer shows itself, how the diagnosis is confirmed, and the biomarkers clinicians test for. https://onco.cc/cancers/clear-cell-ovarian-cancer/#finding-it [5 biomarkers]
- Treatment (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/clear-cell-ovarian-cancer/#treating-it [3 settings, 2 decisions with options]
- Trials and papers (on the hub): Trials recruiting now, the landmark trials, the trials held by this cancer's subtypes, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/clear-cell-ovarian-cancer/#evidence [1 trial, 2 key papers, 3 milestones]
- Biology and targets (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/clear-cell-ovarian-cancer/#science [1 target]
- Countries and centres (own page): Cases by country, the UK and NHS pathway and other country lenses, the expert centres with trials on record, and the centres named on this cancer's subtypes. https://onco.cc/cancers/clear-cell-ovarian-cancer/where-you-are/
- Decisions and support (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/clear-cell-ovarian-cancer/#living-with-it [14 questions, 6 red cards]
- Pipeline and open problems (own page): Everything in development, the medicines held by this cancer's subtypes, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/clear-cell-ovarian-cancer/coming/ [3 medicines, 1 trial, 3 open problems]
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/clear-cell-ovarian-cancer/data/ [14 connected records]

## Standard of care

- Early stage: Complete staging surgery; adjuvant carboplatin-paclitaxel for stage IC and above; observation may be considered for stage IA. ([Carboplatin](https://onco.cc/drugs/carboplatin/), [Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/))
- Advanced or recurrent: Cytoreduction and platinum-based chemotherapy despite modest responses; clinical trials of immunotherapy and ARID1A-directed drugs are preferred where available. ([Pembrolizumab](https://onco.cc/drugs/pembrolizumab/), [ATR and CHK1 inhibitors](https://onco.cc/technologies/atr-chk1-inhibitors/))
- Supportive: Thromboprophylaxis awareness because of the high clot risk. ([Ovarian cancer](https://onco.cc/cancers/ovarian/))

## State of the art

- Recognition of clear cell cancer as a separate disease has ended its lumping into serous trials.
- ARID1A loss creates dependencies (ATR, EZH2, immune) now being exploited in dedicated trials.
- Early detection through endometriosis follow-up is under study in Japan.

## Open problems

- No effective treatment for platinum-resistant disease.
- Which early-stage patients can skip chemotherapy.
- Whether treating endometriosis reduces risk.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Clear-cell_ovarian_carcinoma
- Wikipedia: https://en.wikipedia.org/wiki/Clear-cell_ovarian_carcinoma

## Connected records

- cancers: [Adult granulosa cell tumour of the ovary](https://onco.cc/cancers/granulosa-cell-tumour/), [High-grade serous ovarian cancer](https://onco.cc/cancers/high-grade-serous-ovarian-cancer/), [Low-grade serous ovarian cancer](https://onco.cc/cancers/low-grade-serous-ovarian-cancer/), [Mucinous ovarian cancer](https://onco.cc/cancers/mucinous-ovarian-cancer/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Platinum-resistant ovarian cancer](https://onco.cc/cancers/platinum-resistant-ovarian-cancer/), [Vaginal adenocarcinoma (including DES-associated clear cell adenocarcinoma)](https://onco.cc/cancers/vaginal-adenocarcinoma/)
- key papers: [ARID1A mutations in endometriosis-associated ovarian carcinomas](https://onco.cc/key-papers/paper-wiegand-arid1a-clear-cell-nejm-2010/), [Frequent mutations of the chromatin remodelling gene ARID1A in ovarian clear cell carcinoma](https://onco.cc/key-papers/paper-jones-arid1a-clear-cell-science-2010/)
- drugs: [Carboplatin](https://onco.cc/drugs/carboplatin/), [Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)
- technologies: [ATR and CHK1 inhibitors](https://onco.cc/technologies/atr-chk1-inhibitors/)
- trials: [A Study to Evaluate the Efficacy and Safety of CYH33 in Patients With Recurrent/Persistent Ovary Clear Cell Carcinoma](https://onco.cc/trials/nct05043922/)

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JSON: https://onco.cc/api/v1/entities/clear-cell-ovarian-cancer.json