What are the indications for an endometrial biopsy?

Indications for Endometrial Biopsy

Endometrial biopsy is primarily indicated for abnormal uterine bleeding, particularly in postmenopausal women, and for evaluation of endometrial thickness ≥4 mm on transvaginal ultrasound due to the high risk of endometrial cancer in these scenarios. 1

Primary Indications

Abnormal Uterine Bleeding

• Postmenopausal bleeding: This is the strongest indication as 90% of endometrial cancer cases present with abnormal vaginal bleeding 1
• Persistent or recurrent abnormal uterine bleeding in premenopausal women, especially with risk factors for endometrial cancer 2
• Heavy or irregular menstrual bleeding in women over 35 years 1

Abnormal Endometrial Findings on Imaging

• Endometrial thickness ≥4 mm in postmenopausal women (with or without bleeding) 1
  • For asymptomatic postmenopausal women, a higher threshold of 11 mm may be more specific for cancer detection 3
• Endometrial thickness ≥3 mm with postmenopausal bleeding (higher sensitivity) 1
• Abnormal endometrial appearance on transvaginal ultrasound or saline infusion sonography 1

Risk Factor-Based Indications

Tamoxifen Use

• Women on tamoxifen therapy with:
  • Abnormal vaginal bleeding
  • Endometrial thickness >4 mm on ultrasound 4, 2
  • Annual gynecological examinations recommended for all women on tamoxifen 4

Lynch Syndrome

• Women with Lynch syndrome (hereditary non-polyposis colorectal cancer):
  • Annual endometrial biopsy recommended for cancer surveillance
  • 30-60% lifetime risk of developing endometrial cancer 1

Other High-Risk Conditions

• Unopposed estrogen exposure (including polycystic ovary syndrome, anovulation, nulliparity) 1, 2
• Obesity (BMI >30 increases risk 3-4 fold) 1
• Diabetes mellitus and hypertension 1
• Age >60 years with any suspicious symptoms 5

Diagnostic Algorithm

1. For postmenopausal bleeding:

   • First step: Transvaginal ultrasound to measure endometrial thickness
   • If endometrial thickness ≥3-4 mm: Proceed with endometrial biopsy 1
   • If endometrial thickness <3 mm: Consider clinical risk factors before deciding

2. For asymptomatic postmenopausal women with thickened endometrium:

   • If ≥11 mm: Endometrial biopsy strongly recommended (100% sensitivity for cancer) 3
   • If 4-10 mm: Consider individual risk factors and patient preference

3. For premenopausal women with abnormal bleeding:

   • Biopsy recommended if:
     • Age >35 with persistent abnormal bleeding
     • Any age with risk factors for endometrial cancer
     • Failed medical management of abnormal bleeding 1

Important Considerations

• Sampling adequacy: Insufficient samples require further evaluation as blind sampling may miss focal lesions 6, 7
• Hysteroscopy with directed biopsy is preferred over blind sampling techniques when endometrial cancer is suspected 2
• Pregnancy is the only absolute contraindication to endometrial biopsy 6
• Persistent symptoms despite normal biopsy results warrant further investigation 6, 7

Technique Considerations

• Pipelle or Vabra devices provide high sensitivity (99.6% and 97.1% respectively) for detecting endometrial carcinoma 1
• Hysteroscopy with biopsy should be used when blind sampling is inadequate or when focal lesions are suspected 1, 2
• Endometrial biopsy is less invasive, safer, and more cost-effective than dilation and curettage 1