RT Journal Article SR Electronic T1 EP1064 Clinical and pathologic findings of risk-reducing surgery in high-risk breast/ovarian cancer women JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A560 OP A560 DO 10.1136/ijgc-2019-ESGO.1106 VO 29 IS Suppl 4 A1 M Cardoso A1 C Reis de Carvalho A1 J Aquino A1 L Correia A1 B López A1 M Bernardino A1 AF Jorge YR 2019 UL http://ijgc.bmj.com/content/29/Suppl_4/A560.1.abstract AB Introduction/Background Inherited germline mutations in BRCA1/BRCA2 increase significantly the risk of developing breast and ovarian cancers. For women in whom a BRCA pathogenic variant is identified, risk-reducing bilateral salpingo-oophorectomy (rrBSO) is recommend by age 35 to 40 years or when childbearing is complete. This procedure is associated with reduction of ovarian cancer risk, reduction in breast cancer, cancer-related mortality and overall mortality. The incidence of unsuspected neoplasia in these women varies in the literature.Methodology We performed a retrospective review of all women undergoing risk-reducing surgery between January 2013 and December 2018, in an oncological referral center - Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisbon, Portugal.The purpose of this study was to analyze the results of anatomo-histopathologic examinations and to identify the rate of occult cancer diagnosis in a high-risk population.Results Overall, 83 high-risk women (75 known BRCA1/2 carriers; 8 with unknown mutation status) underwent risk-reducing surgery. The median age at the surgery was 48,76 years and the median body mass index was 25,65 kg/m2. 42,2% (n=35) of these women had personal history of breast cancer. Preoperative CA-125 levels were considered normal in 97,6%(n=81).We performed rrBSO on 22,89%(n=19) of cases and concomitant hysterectomy on 77,1%(n=64). Laparoscopic approach was used in 77,1%(n=64) of procedures. The surgical complication rate was 3.6%(n=3).The anatomopathological analysis of specimens revealed: 5 ovarian serous cystadenoma, 1 adenomatoid tumor of the fallopian tube, 1 ovarian cystic teratoma and 1 ovarian endometrioma. The presence of occult tumor cells, including epithelial ovarian cancer and serous tubal intraepithelial carcinoma, was not reported.Conclusion Risk-reducing surgery is a safe and effective strategy to manage BRCA mutation carriers. Even though our median age at surgery is high, the incidence of unsuspected neoplasia identified in this study was unexpectedly low compared with the current literature.Disclosure Nothing to disclose