Objective: We analyzed tamoxifen use as a malignancy risk factor in women with endometrial polyps. Methods: This retrospective study included 675 women who underwent hysteroscopic polypectomy in 2010 to 2015 at the University of Campinas. Women were divided into tamoxifen use (n = 169) and no tamoxifen use (n = 506) groups. The primary outcome was endometrial cancer prevalence. Dependent variables included age, parity, years since menopause, presence of abnormal uterine bleeding, endometrial pattern on hysteroscopy, and endometrial thickness. Results: There were seven cases of endometrial cancer in the tamoxifen use group (4.14%) and 41 in the no tamoxifen use group (8.1%; P = 0.083). On performing multivariate analysis, tamoxifen use was not a risk factor for endometrial cancer (prevalence ratio 0.51, 95% confidence interval [CI] 0.23-1.14, P = 0.101). The no tamoxifen use group had an increased prevalence of malignancy when women presented with abnormal uterine bleeding (prevalence ratio 3.9, 95% CI 2.08-7.29, P < 0.001), age >60 years (prevalence ratio 2.1, 95% CI 1.12-3.93, P = 0.021), or nulliparous status (prevalence ratio 3.13, 95% CI 1.55-6.35, P = 0.002). The tamoxifen use group had increased prevalence of malignancy when women were >60 years (prevalence ratio 7.85, 95% CI 1.05-58.87, P = 0.006) or nulliparous (prevalence ratio 8.36, 95% CI 2.32-30.11, P < 0.001). Conclusion: Tamoxifen use was not related with a higher prevalence of endometrial cancer in women with endometrial polyps. Abnormal uterine bleeding, age > 60 years, and nulliparous status were associated with malignancy.

Interventions: Hysteroscopic endometrial resection (HER). Measurements/Results: The median (range) age and BMI were 58 (50-87) years and 29 (21-52) kg/m 2 , respectively. Office biopsy failed in 30 (19.8%), was inadequate in 20 (13.2%), identified non-atypical endometrial hyperplasia (NAH) in 21 (14%), AH in 4 (2.6%) and EC in 2 (1.3%) women. HER in 83 women on HRT identified 3 additional cancers (1 each from proliferative, inadequate, NAH group) and 2 AH from NAH. HER in 68 women without HRT identified 6 additional cancers (3 from failed, 1 from inadequate, 1 from NAH, 1 from AH group) and 5 AH (1 from inadequate, 2 from failed, 2 from NAH). Two women with EC refused hysterectomy and are well at 10 and 15 years. Hysterectomy was performed for EC in 9, AH in 2, persistent bleeding in 1. One woman had repeat HER for benign bleeding and 9 (6%) were lost to follow. At a median of 11.5 (7-20) years, 140/151 (92.7%) women with no bleeding were satisfied with their treatment. Conclusions: HER, performed by experienced surgeons, is feasible, safe, and effective for diagnosis and treatment of benign intrauterine pathology, NAH and selected cases of AH and/or EC in women with PMB with and without HRT.