Risk Assessment for Ovarian Cancer in a 60-Year-Old Postmenopausal Woman with Septated Ovarian Cysts
The risk of malignancy is very low (<1%) in this 60-year-old postmenopausal woman with small (≤2 cm) septated ovarian cysts and CA125 values within normal range (20-25 U/mL).
Clinical Features Suggesting Low Risk
- Small cyst size (2 cm and 1.7 cm x 1.3 cm) is associated with a significantly lower risk of malignancy compared to larger cysts in postmenopausal women 1
- Stability of the initial cyst for 1 year without growth is a reassuring feature that suggests benign etiology 2
- Normal CA125 values (20-25 U/mL) are well below the standard threshold of 35 U/mL, which has a specificity of 98.5% for women over 50 years 2
- CT scan with contrast showing only "follicular changes" without evidence of solid components, papillary projections, or other concerning features 2
Risk Stratification Based on Imaging Features
- According to the O-RADS US risk stratification system, septated cysts without solid components or papillary projections are classified as low risk 2
- The presence of a single thin septation (<3 mm) is considered benign with a malignancy risk <0.4% 2
- Multiple septations without papillary projections or solid components are unlikely to be malignant 2
- The IOTA Simple Rules classify features such as unilocular cysts, absence of solid components >7mm, and absence of blood flow as benign (B) features 2
Significance of CA125 Levels
- All patients with CA125 levels <35 U/mL have been found to have benign histopathology regardless of tumor size or ultrasonic features in postmenopausal women 3
- The specificity of CA125 for detecting ovarian cancer is nearly 100% when using thresholds of 30-35 U/mL 2
- False-positive CA125 elevations can occur with benign conditions such as endometriosis, adenomyosis, pelvic inflammatory disease, and benign cysts 2, 4
- This patient's CA125 levels (20-25 U/mL) are well within normal range, further supporting a benign etiology 3
Management Considerations
- For small (<5 cm) septated cysts with normal CA125 levels in postmenopausal women, conservative management with follow-up imaging is appropriate 1
- Color or power Doppler should be included in ultrasound examinations to differentiate true solid components from debris and to assess vascularity patterns 2
- The appearance of a new cyst warrants continued surveillance, but does not significantly increase cancer risk when other features remain reassuring 1
Important Caveats and Pitfalls
- Even with reassuring features, continued surveillance is recommended as some borderline or low-grade malignant lesions may have normal CA125 levels 2, 5
- Larger cysts (>5 cm) have a higher risk of harboring undetected malignancy, as papillary formations or solid parts may be missed by transvaginal ultrasonography 6
- Progressive elevation of CA125 over time, even within normal range, should prompt further evaluation as it may indicate malignancy 2
Conclusion
Based on the current evidence, this patient's presentation with small, stable septated ovarian cysts and normal CA125 values indicates a very low risk (<1%) of malignancy. Continued surveillance with periodic ultrasound and CA125 monitoring is appropriate given the appearance of a new cyst, but immediate intervention is not indicated based on current findings.