CONTEXT: Tamoxifen is used widely as adjunctive therapy for women with breast cancer and it is known its risk of developing endometrial cancer(EC). Nevertheless the current guidelines for the type and frequency of tests for EC screening among these patients are vague and inconsistent. Furthermore many patients, missing clear indications at endometrial biopsy, often undergo at unuseful histeroscopy.The aim of our pilot study was to assess relevant risk factors between anamnestic and ultrasound data so to contribute to assess a risk scoring model applicable in all breast cancer patients undergoing tamoxifen therapy. METHODS, PATIENTS, INTERVENTION and MAIN OUTCOME:The retrospective study was conducted at Sant’Andrea Hospital in Rome. A total of 48 breast cancer patients taking Tamoxifen from 2014 to 2017 were selected and anamnestic datas, ultrasound endometrial features and hystological exam derived from the hysteroscopic biopsies were collected and correlated. RESULTS: The mean age was 54.3 (+/- 10) and BMI was 24,8 (+/- 4,6). Hysteroscopic findings were all benign exept for 4 atypical hyperplasia and 3 cases of EC. Patients with endometrial cancer presented a median BMI of 29.3 vs 24.5 of the patients with a benign endometrial diagnosis (p=0.418). EC patients showed in 100% of the cases a median thickness of 13.4 (+/- 3.1) vs 8.2 (+/-3) of the not affected (p=0.009), in 33% a not well defined miometrium-endometrium interface, and in100% an endometrial homogeneity. About anamnestic features and risk factors of EC, the patients presenting a diagnose of EC were 67% nulliparous, 67% had a previous diagnosis of endometrial polyp, 67% had a previous endometrial hyperlasia, 33% were depressed, 33% were affected by hypertension, 100% presented abnormal uterine bleeding at the moment of our ultrasound examination and hysteroscopy. CONCLUSION: In our pilot study there is a relevant importance in the evaluation of endometrial homogeneity and BMI besides at AUB and endometrial thickness. A confirmed statistical risk of EC would be at a threshold of 13 mm. A BMI of 25-28 would confer a risk of 10-20% while>29 of 20%, AUB of 57%,endometrial ultrasound homogeneity of 30%. These factors shoudln’t be considered alone but all togheter. This study provide relevant data in reducing unuseful hysteroscopy in patients undergoing tamoxifen therapy and further data would let to create a specific risk scoring model always clinically applicable.