Ultrasonography-Based Measurements of Endometrial Thickness in Patients With p53 Abnormal Endometrial Carcinomas.

OBJECTIVE To evaluate prediagnostic endometrial thickness measured by transvaginal ultrasonography (TVUS) in a cohort of patients with endometrial cancer stratified by p53 status to assess accuracy of endometrial thickness as a screening tool in this patient population. METHODS We conducted a retrospective cohort study of patients diagnosed with endometrial cancer who underwent prediagnostic TVUS between 2004 and 2017. Using a tissue microarray, we categorized cases as p53 abnormal (p53abn) or p53 wild type (p53wt) according to the presence or absence of p53 aberrant immunohistochemistry staining. Cases were stratified according to established screening thresholds of 4-mm or less endometrial thickness used to evaluate postmenopausal bleeding. Clinical data were manually abstracted. All patients included underwent surgical staging, including hysterectomy. Student t, χ2, and Fisher exact tests were performed to assess for variables associated with p53abn endometrial carcinoma. Multivariate logistic regression was performed to assess variables associated with cases of endometrial cancer, with false-negative TVUS screening results defined as an endometrial thickness of 4 mm or less. RESULTS Of the 133 patients identified, 60 (45.1%) were classified as p53abn and 73 (54.9%) as p53wt. The median age of the cohort was 66 years (interquartile range 58-74 years), and median body mass index (BMI) was 31.3 (interquartile range 26.8-37.3). Median endometrial thickness was 16 mm (interquartile range 9-22 mm), and 48 patients (36.1%) had submucosal or intramural leiomyomas identified on TVUS. Patients diagnosed with p53abn endometrial cancers were more likely to have thinner endometrial measurements compared with p53wt cases (10 mm [interquartile range 5-18.5 mm] vs 18 mm [interquartile range 13-23 mm], P<.001). At a threshold of 4 mm or less, patients with p53abn endometrial cancer were more likely to screen negative compared with patients with p53wt endometrial cancer (25% vs 4.1%, P<.001). In multivariate analysis, a threshold of 4 mm or less for endometrial thickness, lower BMI (odds ratio [OR] 0.906, 95% CI, 0.833-0.986, P=.023), and p53 status (OR 9.415, 95% CI, 2.441-36.309, P=.001) remained significant predictors of false-negative screening results. CONCLUSION Endometrial thickness assessed by TVUS does not appear to be a reliable screening method in patients diagnosed with p53abn endometrial cancers. The use of endometrial thickness as a screening test for endometrial cancer may miss a significant portion of p53abn cases because of false-negative results. In the presence of postmenopausal bleeding, endometrial tissue sampling should be strongly considered.