Endometrial stripe thickness in the evaluation of postmenopausal bleeding: can we really be reassured by a stripe less than 4mm?

Objectives: Uterine serous carcinoma (USC) is a rare type of endometrial cancer representing less than 10% of uterine cancers, but contributes to up to 50% of the mortality. USC can occur in the setting of a thin, atrophic endometrium. National guidelines support the use of transvaginal ultrasound as one option for initial triage in the evaluation of a woman with postmenopausal bleeding. If the endometrial stripe (EMS) is ≤ 4mm, biopsy can be avoided if no further bleeding occurs. We sought to further investigate the EMS thickness in USC in order to assess the reliability of the current guidelines in this cancer. Methods: A retrospective chart review was conducted using ICD 9 and ICD 10 codes over an 18-year period. We included women with histologically confirmed USC and compared characteristics of women with an EMS≤ 4mm and EMS> 4mm. Statistical calculations were made using Stata (version 15; Stat Corp, College Station, TX). Chi-square tests/Fisher Exact tests were used to compare proportions; 2-tailed t-tests to compare means; and a p-value of Results: 139 women were identified who met criteria. Most women were White, obese, and multiparous. Thirty two (23%) had an endometrial thickness of ≤4 mm, and 107 (77%) women had endometrial thickness of >4 mm. Patients with an EMS ≤ 4mm were found to be younger as compared to women with EMS>4mm (67.9 ±8.3 vs 70.5±9.1; p=0.16). There were no statistically significant differences in presenting symptoms between the groups and post-menopausal bleeding was found to be the most common symptom in each. Conclusions: Uterine serous carcinoma is an aggressive type of endometrial cancer which commonly presents in patients as postmenopausal bleeding. Nearly 25% of patients evaluated with TVUS prior to having a tissue diagnosis of USC were found to have an EMS of