Adult granulosa cell tumor and associated cancers Anna Lund Rasmussen, Finn Lauszus, Anne Hammer PhD Department of Gynecology & Obstetrics Herning Hospital Denmark Context: Adult granulosa cell tumors (AGCTs) comprise 90 % of sex cord stromal ovarian tumors. AGCT is characterized by its ability to produce excessive amounts of estrogens in contrast to the more common epithelial neoplasm. Women are usually diagnosed at an early stage due to estrogen-dependent symptoms: -Abnormal vaginal bleeding -Postmenopausal bleeding. The prognosis of AGCT is challenged by a tendency of late relapses and requires a long follow up time. Only limited information exist about GCTs and potential association to other hormone-related neoplasms such as breast cancer and endometrial cancer Our study investigated the incidence of breast and endometrial cancer in patients diagnosed with AGCT and the influence on the prognosis of the AGCT women . Methods: Registry data were retrieved and vallidated via social security number, PatoWeb, Hospital charts and Death Registry Acknowledgments: . Astrid Petersen, Department of Pathology, Aalborg Hospital Denmark. Distribution of hormone dependent cancers Survival of AGCT and AGCT+breast/endometrial cancer (AGCT stage I only) Results: During 1964-2016 a total of 468 Danish women were diagnosed with AGCT with a median follow-up of 9 years . The vast majority (93%) were diagnosed in stage I. Among AGCT patients, the risk of breast cancer was nearly 5-fold increased (RR= 4.7 (2.9-7.2)), whereas the risk of endometrial cancer was almost 14-fold increased (RR of 13.7 (8.8-19.6)). Importantly, the survival rate was poorer in women with a diagnosis of AGCT + breast or endometrial cancer compared with AGCT only. Conclusion: Follow-up regime is needed. Breast screen and endometrial sampling. Correspondence: Anna.rasmussen@auh.rm.dk . Relative risk of hormone dependent cancer in AGCT Observed/expected cancers (95%CI) Breast cancer Endometrial cancer