RESUMEN
We conducted a prospective observational study investigating the clinical relevance of endometrial thickness (ET) and abnormal uterine bleeding (AUB) on endometrial cancer (EC) risk in a cohort of postmenopausal patients undergoing diagnostic hysteroscopy and endometrial biopsy. Patients were divided into two groups according to the indication of diagnostic hysteroscopy: ET_Group (asymptomatic patients with endometrial thickness ≥ 4 mm) and AUB_Group (patients with a history of abnormal uterine bleeding). We further divided the AUB_Group into two subgroups based on endometrial thickness (AUB_Subgroup1: ET < 4 mm; AUB_Subgroup2: ET ≥ 4 mm). The primary outcome was the risk of endometrial cancer and atypical hyperplasia according to the indications of diagnostic hysteroscopy (AUB, ET ≥ 4 mm or both). The secondary outcome was to determine the best cut-off value of endometrial thickness to predict endometrial cancer in asymptomatic postmenopausal women. The prevalence of endometrial cancer and atypical hyperplasia in AUB_Group and ET_Group was 21% and 6.7% respectively. As well as for EC alone, higher prevalence of both conditions was observed in AUB_Subgroup2 (29.3%) in comparison to AUB_Subgroup1 (10.6%; p < 0.001). In asymptomatic patients the cut-off of endometrial thickness that showed the best sensitivity and specificity to diagnose endometrial cancer (100% and 80% respectively) was 11 mm (AUC of 91.4%; Expß: 1067; CI 95%). In conclusion, considering the high risk of neoplasia, diagnostic hysteroscopy with endometrial biopsy should be mandatory in cases of abnormal uterine bleeding in postmenopausal patients. Moreover, we want to emphasize the need for further evidence stating the clinical relevance of endometrial thickness value in asymptomatic patients and the impact of individual risk factors on endometrial cancer development.