What are the next steps for a patient with an O-RADS (Ovarian-Adnexal Reporting and Data System) 2 score?

Management of O-RADS 2 Lesions

For patients with an O-RADS 2 score (almost certainly benign lesions with <1% risk of malignancy), follow-up ultrasound or no follow-up is recommended depending on specific characteristics of the lesion and patient menopausal status.

Definition and Risk Assessment

• O-RADS 2 represents the "almost certainly benign" category with less than 1% risk of malignancy 1
• This category comprises the majority of unilocular cysts less than 10 cm, including simple cysts, nonsimple unilocular cysts with smooth walls, and classic benign lesions 1
• Recent research confirms the extremely low malignancy rate in O-RADS 2 lesions, with one study showing less than 1% (1 of 157) of surgically resected O-RADS 2 lesions were malignant 2
• External validation studies have demonstrated 0% malignancy rate (0 of 100) for lesions classified as O-RADS 2 3

Management Based on Lesion Type and Size

Simple Cysts

• Premenopausal women:

  • Simple cysts ≤3 cm: No follow-up needed 1, 4
  • Simple cysts >3 cm to ≤5 cm: No additional management required 4
  • Simple cysts >5 cm but <10 cm: Follow-up ultrasound in 8-12 weeks 1, 5

• Postmenopausal women:

  • Simple cysts ≤3 cm: No follow-up needed 4
  • Simple cysts >3 cm but <10 cm: Follow-up in 1 year, with consideration of annual follow-up for up to 5 years if stable 1, 5

Classic Benign Lesions <10 cm

• Typical hemorrhagic cyst:

  • <5 cm: Referral to US specialist, gynecologist, or MRI 1

  • 5 cm but <10 cm: Follow-up in 8-12 weeks; if persists or enlarges, referral to US specialist, gynecologist, or MRI 1

• Typical dermoid cyst <10 cm:

  • Referral to US specialist, gynecologist, or MRI 1
  • With confident diagnosis, if not removed surgically, annual US follow-up should be considered 1

• Typical endometrioma <10 cm:

  • US specialist or MRI if there is enlargement, changing morphology, or a developing vascular component 1

• Simple paraovarian cyst:

  • No follow-up needed; optional single follow-up study in a year 1

• Typical peritoneal inclusion cyst:

  • Referral to gynecologist 1

• Typical hydrosalpinx (any size):

  • Referral to gynecologist 1

Non-simple Unilocular Cyst with Smooth Inner Margin

• Premenopausal women:

  • <3 cm: No follow-up needed 1

  • 3 cm but <10 cm: Follow-up in 8-12 weeks; if concerning, US specialist 1

• Postmenopausal women:

  • 3 cm but <10 cm: US specialist 1

Important Considerations

• Transvaginal ultrasound is preferred for evaluation but may be augmented by transabdominal or transrectal approaches as needed 1
• The size of the lesion should be measured by the largest diameter regardless of the plane 1
• In cases of multiple lesions, each should be separately characterized, with management driven by the lesion with the highest O-RADS score 1
• The O-RADS US system is based on an average-risk patient with no acute symptoms and no substantial risk factors for ovarian cancer 1

Common Pitfalls to Avoid

• Unnecessary surgical intervention for O-RADS 2 lesions - a recent study showed that 42% of surgically resected lesions met O-RADS 2 criteria and could have been managed conservatively 2
• Failing to perform adequate follow-up for cysts >5 cm, as larger cysts may be more challenging to evaluate completely 5
• Not distinguishing between simple cysts and other cyst types which have different management protocols 4
• Overlooking the possibility of functional cysts in premenopausal women, which typically resolve within 8-12 weeks 5

When to Consider MRI

• When ultrasound evaluation is incomplete (O-RADS 0) due to technical factors 1
• For further characterization of lesions with uncertain features 1
• MRI using the O-RADS MRI scoring system has shown high diagnostic performance for characterization of US-indeterminate adnexal lesions 6