# Low-grade serous ovarian cancer

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

## TL;DR

Low-grade serous cancer is the slow-growing, chemotherapy-resistant cousin of the common ovarian cancer. Surgery and hormone therapy are its mainstays, and MEK inhibitors, alone or combined with a FAK inhibitor, are the first drugs shown to shrink it reliably.

## Summary

Low-grade serous carcinoma is a distinct disease with wild-type TP53 and mutations in the MAPK pathway (KRAS, BRAF, NRAS) in about half of cases; it often arises from a serous borderline tumour and expresses oestrogen receptors. Complete surgical removal matters more than in high-grade disease because chemotherapy response rates are low; letrozole or other aromatase inhibitors are used as maintenance and for recurrence. The GOG 281 trial showed that the MEK inhibitor trametinib nearly doubled progression-free survival compared with standard chemotherapy or hormone therapy in recurrent disease, and the combination of avutometinib and defactinib was approved in the United States in 2025 for KRAS-mutant recurrent disease after the RAMP 201 trial.

## Fields

- Kind: Cancer
- Last checked: 2026-09-17
- Also known as: LGSOC; Low-grade serous carcinoma
- Tags: subtype-page
- Group: gynaecologic
- Burden: About one in twenty ovarian cancers, affecting younger women, with a median age in the forties; it grows slowly but resists chemotherapy, so patients live for years with disease that is hard to eradicate.
- Subtypes: KRAS-mutant (most responsive to MEK and RAF/MEK inhibition); BRAF or NRAS-mutant; MAPK wild-type; Arising from serous borderline tumour
- Biomarkers: KRAS, BRAF and NRAS mutations; Oestrogen and progesterone receptor expression; Wild-type TP53 (distinguishes it from high-grade); CA-125 (less reliable than in high-grade disease)

## 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/low-grade-serous-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/low-grade-serous-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/low-grade-serous-ovarian-cancer/#what-it-is [4 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/low-grade-serous-ovarian-cancer/#finding-it [4 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/low-grade-serous-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/low-grade-serous-ovarian-cancer/#evidence [2 trials, 3 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/low-grade-serous-ovarian-cancer/#science [4 targets]
- 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/low-grade-serous-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/low-grade-serous-ovarian-cancer/#living-with-it [15 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/low-grade-serous-ovarian-cancer/coming/ [5 medicines, 2 trials, 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/low-grade-serous-ovarian-cancer/data/ [24 connected records]

## Standard of care

- First line: Complete cytoreductive surgery; carboplatin-paclitaxel followed by letrozole maintenance, or letrozole alone in selected patients. ([Carboplatin](https://onco.cc/drugs/carboplatin/), [Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/), [Letrozole (and other aromatase inhibitors)](https://onco.cc/drugs/letrozole/))
- Recurrent disease: Trametinib (GOG 281) or avutometinib plus defactinib for KRAS-mutant tumours; aromatase inhibitors; secondary surgery where complete resection is possible. ([Trametinib](https://onco.cc/drugs/trametinib/), [Avutometinib + defactinib](https://onco.cc/drugs/avutometinib-defactinib/), [Letrozole (and other aromatase inhibitors)](https://onco.cc/drugs/letrozole/))
- Maintenance: Letrozole after first-line treatment, continued for years while tolerated. ([Letrozole (and other aromatase inhibitors)](https://onco.cc/drugs/letrozole/))

## State of the art

- GOG 281 was the first randomised trial in this rare disease and made trametinib a standard option.
- Avutometinib-defactinib is the first approval specific to low-grade serous cancer.
- Hormone maintenance is replacing chemotherapy in first-line care.

## Open problems

- Whether first-line chemotherapy adds anything to surgery and hormone therapy.
- Options for MAPK wild-type tumours.
- Living for decades with a slow but incurable disease.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Ovarian_cancer
- Wikipedia: https://en.wikipedia.org/wiki/Ovarian_cancer

## Connected records

- cancers: [Adult granulosa cell tumour of the ovary](https://onco.cc/cancers/granulosa-cell-tumour/), [Clear cell ovarian cancer](https://onco.cc/cancers/clear-cell-ovarian-cancer/), [High-grade serous ovarian cancer](https://onco.cc/cancers/high-grade-serous-ovarian-cancer/), [Mucinous ovarian cancer](https://onco.cc/cancers/mucinous-ovarian-cancer/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Platinum-sensitive ovarian cancer](https://onco.cc/cancers/platinum-sensitive-ovarian-cancer/)
- key papers: [GOG 281/LOGS: trametinib versus standard of care in recurrent low-grade serous ovarian cancer](https://onco.cc/key-papers/paper-gog-281-trametinib-lgsoc-gershenson-lancet-2022/), [Hormonal maintenance therapy for women with low-grade serous cancer of the ovary or peritoneum](https://onco.cc/key-papers/paper-gershenson-hormonal-maintenance-lgsoc-jco-2017/), [RAMP 201: avutometinib with or without defactinib in recurrent low-grade serous ovarian cancer](https://onco.cc/key-papers/paper-ramp-201-avutometinib-defactinib-lgsoc-jco-2025/)
- drugs: [Avutometinib + defactinib](https://onco.cc/drugs/avutometinib-defactinib/), [Carboplatin](https://onco.cc/drugs/carboplatin/), [Letrozole (and other aromatase inhibitors)](https://onco.cc/drugs/letrozole/), [Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/), [Trametinib](https://onco.cc/drugs/trametinib/)
- people: [David M. Gershenson](https://onco.cc/people/david-gershenson/), [Susana Banerjee](https://onco.cc/people/susana-banerjee/)
- targets: [FAK (PTK2)](https://onco.cc/targets/fak/)
- trials: [A Study of Avutometinib (VS-6766) + Defactinib (VS-6063) in Recurrent Low-Grade Serous Ovarian Cancer](https://onco.cc/trials/nct06072781/), [A Study of Avutometinib + Defactinib in Recurrent Low-Grade Serous Ovarian Cancer in Japanese Patients](https://onco.cc/trials/nct06682572/)

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JSON: https://onco.cc/api/v1/entities/low-grade-serous-ovarian-cancer.json