From the Guidelines
An endometrial thickness of 5 mm or more in a postmenopausal woman is a concern.
Postmenopausal Endometrial Thickness
- The thickness of the endometrial lining is a significant factor in diagnosing endometrial cancer in postmenopausal women 1.
- A thickness of 4 mm or less conveys a negative predictive value for cancer of nearly 100% 1.
- However, a thickened endometrium of 5 mm or more generally prompts evaluation by endometrial tissue sampling 1.
- Other studies suggest using a cut-off point of 3 or 4 mm for endometrial thickness, followed by endometrial sampling 2, 3.
- It is essential to note that while ultrasonography is sensitive for evaluating endometrial thickness, it cannot reliably determine the etiology of endometrial thickening 1.
- Saline infusion sonography and hysteroscopy with biopsy can be used to further diagnose and distinguish between focal and diffuse pathology 2, 3.
From the Research
Endometrial Lining Thickness Post-Menopause
The thickness of the endometrial lining post-menopause that is a concern can be evaluated based on several studies.
- A study published in 2005 4 found that an endometrial thickness of more than 3 mm in postmenopausal women with endometrial fluid collection on sonography should undergo endometrial sampling.
- Another study from 2021 5 suggested using an endometrial thickness of 10 mm or above as a cutoff threshold to offer endometrial biopsy or outpatient hysteroscopy for asymptomatic postmenopausal women.
- A 2004 study 6 found that no patient had carcinoma when the endometrium was less than 5 mm thick, but 18.5% did when the thickness exceeded 9 mm.
- A 2016 study 7 found that an endometrial thickness of or above 15 mm was associated with carcinoma, with a negative predictive value of 98.5% and a 0.06% risk of cancer.
- A systematic review and meta-analysis from 2018 8 found that the relative risk of endometrial cancer and/or endometrial hyperplasia with atypia in the ≥11 mm group was 2.59 (95% CI: 1.66-4.05) compared to women with endometrial thickness <11 mm.
Key Findings
- The threshold for endometrial sampling among postmenopausal patients without vaginal bleeding may be an endometrial lining of 10-15 mm or above 5, 7, 8.
- An endometrial thickness of more than 3 mm in postmenopausal women with endometrial fluid collection on sonography should undergo endometrial sampling 4.
- The risk of endometrial cancer and/or endometrial hyperplasia with atypia increases with increasing endometrial thickness 6, 7, 8.