Low-grade serous ovarian cancer
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.
Overview
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.
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.
Anatomy and lymph node drainage
Most high-grade ovarian cancers begin at the tip of the fallopian tube; endometrial cancer lines the uterus, cervical cancer starts at the transformation zone; each drains to a different node group.
- Fallopian tube fimbria (origin of high-grade serous)Arising from serous borderline tumour
- Ovary (other histologies, germ cell)Arising from serous borderline tumour
- EndometriumArising from serous borderline tumour
- Myometrium (uterine sarcoma)
- Placental site (gestational trophoblastic)
- Cervix, transformation zone
- Vulva
- obturator and external iliac
- internal iliac
- para-aortic (ovary, high uterus)
- inguinal (vulva)
Same organ: High-grade serous ovarian cancer, Clear cell ovarian cancer, Mucinous ovarian cancer, Adult granulosa cell tumour of the ovary, Ovarian cancer, Endometrial cancer, Cervical cancer, Vulvar cancer, Gestational trophoblastic neoplasia, Uterine sarcoma, Vaginal cancer
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.
- AI in radiologyEstablished
- cfDNA fragmentomicsEstablished
- Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood)Standard of care
- DNA methylation profilingEstablished
- HCC surveillance in cirrhosis (ultrasound + AFP)Standard of care
- High-risk pancreatic surveillance (CAPS / PRECEDE)Established
- A 28-day national pathway for people with a positive multi-cancer blood test
- A breath test to rule out cancer in people with vague symptoms
- A cancer blood test for older people arriving at A&E with unexplained symptoms
- A legislated, publicly reported 28-day standard from urgent referral to diagnosis
- A live national dashboard of stage at diagnosis as the scorecard for early detection
- A single 'cancer check at 60' appointment bundling all screening tests
Background: Alpha-fetoprotein (AFP), Barrett's oesophagus, CA 19-9, Early detection, Faecal immunochemical test (FIT). Also on OnCo: Symptoms and red flags · Early detection roadmap.
Cases by country
No country-level case numbers. This cancer is not mapped to a GLOBOCAN site.
Complete cytoreductive surgery; carboplatin-paclitaxel followed by letrozole maintenance, or letrozole alone in selected patients.
Trametinib (GOG 281) or avutometinib plus defactinib for KRAS-mutant tumours; aromatase inhibitors; secondary surgery where complete resection is possible.
Subtypes & biomarkers
top- KRAS-mutant (most responsive to MEK and RAF/MEK inhibition)
- BRAF or NRAS-mutant
- MAPK wild-type
- Arising from serous borderline tumour
- 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)
How often this target appears
- 2004Two-tier grading separates low-grade from high-grade serous cancer (MD Anderson)
- 2022GOG 281: trametinib doubles progression-free survival
- 2025Avutometinib plus defactinib approved for KRAS-mutant disease
What is in development for Low-grade serous ovarian cancer, drawn from the whole corpus: 0 items. Drugs are grouped by the most advanced trial phase they have reached anywhere; approved treatments sit under standard of care. Technologies are the methods being tested for this cancer, trials are the studies recorded here, and ideas are proposals not yet in a trial.
Nothing recorded in development for this cancer yet.
Open problems and what is being done
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.
Trials
topTrials recruiting now
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Expert centres
topExpert centres
- Alliance for Clinical Trials in OncologyChicago, IL, USvia Carboplatin
- German Breast Group (GBG)Neu-Isenburg, DEvia Carboplatin
- Institute of Oncology LjubljanaLjubljana, SIvia Carboplatin
Questions to ask
topQuestions to ask your oncologist about Low-grade serous ovarian cancer
Newly diagnosed
- What is my exact diagnosis, stage, and grade, and which tests established them?Why: Everything else follows from an accurate stage and subtype.
- Which biomarkers have been tested on my tumour (for example KRAS, BRAF and NRAS mutations, Oestrogen and progesterone receptor expression, Wild-type TP53, CA-125), and what were the results?Why: These results decide eligibility for targeted therapy, immunotherapy, and trials.
- Which subtype is my cancer, and does that change the recommended treatment?Why: Recognised subtypes for this cancer include KRAS-mutant, BRAF or NRAS-mutant, MAPK wild-type.
- Is germline (inherited) genetic testing recommended for me or my family?Why: Inherited variants can change treatment and matter for relatives.
First line
- For my situation (first line), which of the standard options do you recommend and why?Why: Guideline options include: Complete cytoreductive surgery; carboplatin-paclitaxel followed by letrozole maintenance, or letrozole alone in selected patients.
- Am I a candidate for Carboplatin, Paclitaxel / nab-paclitaxel, Letrozole (and other aromatase inhibitors), and what side effects should I expect?Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
Recurrent disease
- For my situation (recurrent disease), which of the standard options do you recommend and why?Why: Guideline options include: Trametinib (GOG 281) or avutometinib plus defactinib for KRAS-mutant tumours; aromatase inhibitors; secondary surgery where complete resection is possible.
- Am I a candidate for Trametinib, Avutometinib + defactinib, Letrozole (and other aromatase inhibitors), and what side effects should I expect?Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
Any stage
- Would a second opinion at a high-volume centre change anything, and can you help arrange it?Why: Rare or high-stakes decisions benefit from a centre that treats many similar patients.
- What supportive care (symptom control, nutrition, exercise, mental health, financial help) is available from the start?Why: Supportive care improves quality of life and helps patients complete treatment.
- I read that “Whether first-line chemotherapy adds anything to surgery and hormone therapy”. How does that affect my plan?Why: Open problems are where trials and second opinions matter most.
- I read that “Options for MAPK wild-type tumours”. How does that affect my plan?Why: Open problems are where trials and second opinions matter most.
Print this page for your appointment (your browser's print command). These prompts are for discussion; your clinical team knows your case.
Direct links plus the targets, companies, and technologies of this cancer's products.
technologies
4targets
3drugs
5companies
3Latest papers
topQuery for this cancer: (TITLE:"Low-grade serous ovarian cancer" OR ABSTRACT:"Low-grade serous ovarian cancer" OR TITLE:"LGSOC" OR ABSTRACT:"LGSOC" OR TITLE:"Low-grade serous carcinoma" OR ABSTRACT:"Low-grade serous carcinoma") AND (treatment OR therapy OR trial OR survival OR diagnosis). Results are unfiltered search hits about Low-grade serous ovarian cancer, not a curated reading list.
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