RT Journal Article SR Electronic T1 EP1256 Long-term results of high-risk stage I endometrial cancer depending on the morphological tumor type JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A631 OP A631 DO 10.1136/ijgc-2019-ESGO.1262 VO 29 IS Suppl 4 A1 S Taranenka A1 A Shushkevich A1 S Mavrichev YR 2019 UL http://ijgc.bmj.com/content/29/Suppl_4/A631.1.abstract AB Introduction/Background We evaluated the long-term results of treatment and effect of adjuvant chemotherapy on the survival rate of patients with high-risk EC stage I.Methodology In the retrospective study were include 225 patients who underwent treatment in Belarussian cancer clinics between 2006–2010. EC Ib G1 stage and nonendometrioid stage I cancer (serous, clear cell, undifferentiated carcinoma, carcinosarcoma) were included in the study. We received all the data from the Belarusian cancer registry.Results The overall (OS), cancer-specific (CSS) and disease-free (DSF) 5-year survival rate in high-risk EC was 66.7±3.2, 77.4±2.9%, 77.0±2.9%. 10-year old ¬ 53.7±4.5, 69.7±4.2 and 69.3±4.2% respectively. There were no statistically significant differences in the survival depending on morphological tumor type, but the endometrioid carcinoma of the Ib G3 stage is defined as a most favourable form of the high-risk EC, and the undifferentiated carcinoma and carcinosarcoma are the most unfavourable forms. The were no statistically significant differences in OS, CSS and DFS between the endometrioid carcinoma of the Ib G3 stage EC and nonendometrioid forms of the EC stage I. Adjuvant chemotherapy did not improve the long-term outcome of treatment in general, as well as separately in the Ib G3 stage of the endometrioid carcinosarcoma and the nonendometrioid EC stage I.Conclusion International collaborative research may define the role of chemotherapy in patients treatment with high-risk ECDisclosure Nothing to disclose