What is the recommended initial approach for endometrial cancer scanning?

Recommended Initial Approach for Endometrial Cancer Scanning

The recommended initial approach for endometrial cancer scanning is transvaginal ultrasonography (TVUS) combined with endometrial biopsy, with TVUS serving as the first-line imaging modality followed by histological confirmation through biopsy or dilation and curettage. 1, 2

Initial Diagnostic Approach

• Transvaginal ultrasonography (TVUS) is the preferred first-line imaging modality for evaluating the endometrium due to its excellent accessibility, low cost, and ability to effectively assess for structural causes of abnormal uterine bleeding 1, 2
• TVUS should be combined with transabdominal ultrasound whenever possible for complete assessment of pelvic structures 3
• Hysteroscopy may be performed alongside TVUS to obtain a representative biopsy or for removal of target lesions 1
• Endometrial sampling by biopsy or dilation and curettage (D&C) is necessary for histological diagnosis of endometrial cancer 1

Evaluation Algorithm Based on Menopausal Status

For Postmenopausal Women:

• In postmenopausal women with bleeding, TVUS measurement of endometrial thickness is crucial 3, 4
• An endometrial thickness ≤4 mm has >99% negative predictive value for endometrial cancer 3, 4
• If endometrial thickness is ≥5 mm, endometrial biopsy is mandatory 3, 5
• Persistent or recurrent bleeding despite normal initial findings warrants further evaluation with hysteroscopy and directed biopsy 2, 4

For Premenopausal Women:

• TVUS is still the initial imaging modality of choice 1
• Women with risk factors (unopposed estrogen exposure, tamoxifen therapy, Lynch syndrome) may require more aggressive evaluation 2
• Endometrial biopsy is indicated for abnormal uterine bleeding, particularly in women with risk factors 2

Advanced Imaging Techniques

• Sonohysterography (saline infusion sonography) is helpful to distinguish between focal and diffuse pathology when initial TVUS is inconclusive or further imaging characterization is needed 1, 3
• MRI is considered the most accurate imaging technique for preoperative assessment of endometrial cancer due to its excellent soft tissue contrast resolution 1
• Dynamic contrast-enhanced MRI and T2-weighted images are useful for assessing myometrial invasion (98% accuracy) and cervical stromal invasion (90% accuracy) 1
• FDG-PET-CT demonstrates high specificity for detecting distant metastases and lymph node involvement, and can be considered as an additional diagnostic procedure 1

Diagnostic Accuracy and Pitfalls

• Endometrial sampling techniques like Pipelle or Vabra devices have high sensitivity (99.6% and 97.1% respectively) for detecting endometrial carcinoma 2, 3
• Blind endometrial sampling has a false-negative rate of approximately 10%, requiring follow-up with D&C if symptoms persist 2
• TVUS is sensitive for evaluating endometrial thickness but cannot reliably determine the etiology of endometrial thickening 3
• No single examination is sufficiently sensitive and specific to distinguish between stage I and stage II disease 1

Special Considerations

• For women with Lynch syndrome (30-60% lifetime risk of endometrial cancer), yearly endometrial biopsy starting at age 30-35 is recommended for surveillance 2, 3
• In patients with suspected advanced disease, additional imaging tests (thoracic and abdominal CT scan and/or FDG-PET-CT) may be considered 1
• CA125 is not of diagnostic value for endometrial cancer but may be useful in monitoring clinical response in patients with extrauterine disease 1, 2

Important Caveats

• TVUS is not an appropriate screening tool for endometrial cancer in asymptomatic postmenopausal women without bleeding 4, 5
• An incidentally discovered endometrial thickness >4 mm in an asymptomatic postmenopausal woman does not routinely require evaluation 4
• Abnormal echogenicity and texture of the endometrium may correlate with significant underlying uterine pathology even when thickness is normal 3
• Focal endometrial lesions are better evaluated with hysteroscopy with directed biopsy rather than blind endometrial sampling 3