creation date: 2026-01-05 14:51
tags: Pathologies
Ovarian Cancer
Background
Definitions
Ovarian cancer is characterized by the abnormal growth of cells in the ovaries. It is often diagnosed at an advanced stage which results in worse prognoses.
The majority of ovarian cancer originate from the epithelium (95%) while nonepithelial ovarian cancers account for 5%.
Etiology and Risk Factors
While the etiology is poorly understood, risk factors associated with ovarian cancer include:
- Advanced age (peak incidence 45-65 depending on subtype)
- Early onset menarche
- Late onset menopause
- Family history of breast/ovarian cancer
- Nulliparity
- Obesity
- Perineal talc use
- Smoking
- Endometriosis
- Hormone replacement therapy
These risk factors can be summarized as factors that increase total lifetime ovulations, inflammation, or genetic risk.
Subtype
Epithelial
High-grade ovarian serous cancer
- Most common subtype
- Associated with TP53 and BRCA1/2
- Significant nuclear atypia, hyperchromatic nucleoli, increased mitotic activity
Low-grade ovarian serous cancer
- Accounts for 10% of epithelial ovarian cancer
- Small papillae with uniform nuclei and little mitotic activity
Endometrioid ovarian cancer
- 10% of epithelial ovarian cancer
- Histologically similar to endometrial endometrioid cancer
Clear-cell ovarian cancer
- <5% of ovarian cancer
- Histologically may have tubules, solid areas, and complex paillae with cellular clearing and characteristic hobnail growth pattern
Mucinous ovarian cancer
- 2% of epithelial ovarian cancers
- Favourable prognosis due to earlier stage diagnosis
- Histologically similar to metastatic mucinous appendix tumour - routine appendectomy common
Non-epithelial
Metastatic Spread
The spread of ovarian cancer follows regional lymphatic drainage of the ovaries and fallopian tube. The most common site for distal metastasis is the peritoneum including the omentum and visceral sufaces.
Hematogenous spread is rare except for in advanced-stage disease.
Clinical Presentation
Signs & Symptoms
Incidental findings (asymptomatic) is common early disease.
The most common presentation is subacute. Symptoms include:
- Bloating or abdominal distention
- Urinary urgency or frequency
- Difficulty eating, nausea, anorexia, or early satiety
- Pelvic or abdominal pain
- Postmenopausal bleeding
In advanced disease, acute presentation includes:
- Ascites (production of fluid from tumour cells and metastasis on diaphragm prevents fluid from flowing out)
- Pleural effusion
- Bowel obstruction (nausea, vomiting, abdominal mass)
- Venous thromboembolism
History & Physical Exam
Initial physical exam should evaluate for extent of suspicion for malignancy. A pelvic exam should be performed for an adnexal mass.
History and physical should assess for symptoms associated with metastatic disease (eg. GI, lymphadenopathy).
Additionally, a breast exam, lymph node exam, and abdominal exam should be performed.
Diagnosis
Criteria
Ovarian cancer is a histologic diagnosis. Tissue is obtained during surgical removal of an ovary or fallopian tube or viwht biopsy of the peritoneum.
Work-up
Initial imaging
If initial finding is an adnexal mass, transvaginal ultrasound is indicated for suspicion of malignancy. The O-RADS ultrasound risk stratification system can be used to determine next steps:
- O-RADS 0: inadequate visualization due to technical factors; repeat U/S or use another modality
- O-RADS 1: physiologic adnexal lesions with no abnormal findings (only premenopausal); 0% risk of malignancy
- O-RADS 2: likely benign (simple cyst or unilocular cyst with internal echos but smooth walls and sized <10 cm); <1% risk of malignancy
- O-RADS 3: possible malignancy (O-RADS 2 cysts but >10 cm, unilocular cyst with irregular walls, multilocular cysts without solid component); 1-10% risk of malignancy
- O-RADS 4: indeterminate risk features; 10-50% riskof malignancy; consider referal based on menopausal status, MRI, and serum biomarkers
- O-RADS 5: high risk features (solid lesions, papillary projections, multilocular cysts with solid component, associated ascites or peritoneal nodules); ≥50% risk of malignancy
Further investigations
Serum biomarkers can be used:
- CA 125 (>35 U/mL is suggestive of malignancy)
Additionally, unclear ultrasound may require MRI to further characterize adnexal mass. MRI can further stratify mass via the O-RADS MRI scale (AdnexMR 1 - AdnexMR 5).
CT abdomen, pelvis, and thorax is often done prior to MRI to evaluate for extent of disease and preoperative planning due to better availability.
Differential
The differential primarily consist of other adnexal masses, especially those on the ovary.
Red Flags / Complications
Management
Treatment of ovarian cancer is through gynecologic oncology referral. This may involve:
- Surgical therapy
- Chemotherapy
- Hormone therapy