Introduction/Background Endometrial cancer with a history of breast cancer (BC) is a specific condition. As compared to the general population, breast cancer survivors are at an increased risk of developing any secondary cancer with an excess risk of 30% . Endometrial cancer (EC), is the most frequently observed secondary malignancy among breast cancer patients. We aimed to investigate the incidence and the characteristics of EC in patients with previous breast cancer .

Methodology The records of 49 patients with previous history of BC and who underwent pipelle endometrial biopsy between 2015–2020 were evaluated retrospectively. Data were evaluated for age, menopausal status, tamoxifen use and endometrial thickness, surgery and the pathologic characteristics of endometrial cancer patients.

Results Among 49 endometrial biopsies, endometrial cancer was diagnosed in 10 (20.4%), atypical endometrial hyperplasia was diagnosed in 3 patients (6,12%), nonatypical endometrial hyperplsia in 8 (16,32%), endometrial polyp and normal hystology was noted in 28 patients (57,14%). Since 2 out of 10 patients diagnosed with endometrial cancer were operated in another center, we evaluated the data of 8 endometrial cancer cases..(40.1%). The characteristics of the patients who were diagnosed with endometrial cancer and underwent surgical staging are summarized in table 1.

Conclusion Abnormal uterine bleeding, increased endometrial thickness in BC patients treated with tamoxifen, found to be associated with the formation of endometrial cancer. Based on these findings, breast cancer patients receiving tamoxifen therapy, especially postmenopausal patients, should be followed closely and carefully evaluated when they have abnormal bleeding.