At what endometrial thickness should biopsy be performed in postmenopausal women without vaginal bleeding?

With no consensus regarding the normal endometrial thickness in postmenopausal women without vaginal bleeding, there are no guidelines for clinicians to follow on when to biopsy, if at all, in an older patient presenting with pelvic pain but no bleeding.

To determine at what endometrial thickness biopsy would be optimal, Michelle Louie, MD, and colleagues from Magee Women’s Hospital in Pittsburgh, Pennsylvania, performed a retrospective cohort analysis of postmenopausal women aged 50 or older who underwent transvaginal ultrasound (TVUS) for indications other than vaginal bleeding. They presented their findings in an abstract at the 43rd AAGL Global Congress in Vancouver, Canada.

Details of the study

Patients were included if they had an endometrial lining of 4 mm or greater and excluded if they had a history of tamoxifen use, hormone replacement, endometrial ablation, hereditary cancer syndrome, or no available pathology results.

Of 462 biopsies, 435 (94.2%) had benign pathology, nine (2.0%) had carcinoma, and seven (1.5%) had atypical hyperplasia.

Endometrial thickness of 14 mm or greater was associated with atypical hyperplasia (odds ratio [OR], 4.29; P = .02), with a negative predictive value of 98.3%. A thickness of 15 mm or greater was associated with carcinoma (OR, 4.53; P = .03), with a negative predictive value of 98.5%.

Under 14 mm, the risk of hyperplasia was low, the authors found, at 0.08%. Below 15 mm, the risk of cancer was 0.06%.

They found no significant associations between endometrial lining TVUS appearance, age, parity, body mass index, diabetes, hypertension, hyperlipidemia, and carcinoma or atypical hyperplasia.

When biopsy might not be necessary

Therefore, regardless of conventional risk factors for endometrial cancer, if a postmenopausal woman reports pelvic pain without vaginal bleeding, and is found to have a thickened endometrial lining of less than 14 mm on TVUS, biopsy might not be warranted, conclude the study authors.