Introduction/Background BRCA1/2 mutations, integral drivers of homologous recombination deficiency (HRD), are observed in up to 15–25% of patients with primary advanced high-grade ovarian cancer (OC). Maintenance treatment with PARPi has significantly increased PFS of those patients, particularly in patients with HRD. Moreover, BRCA mutations at the DNA-binding site (DNA-BS) of BRCA1 and BRCA2 were also predictive of PARPi effectivity. Data of BRCA1/2 mutation frequencies and location of BRCA1/2 mutations in early-stage OC are sparse. Methodology Retrospective analyses of data from a prospectively running database from Kliniken-Essen-Mitte, a tertiary, ESGO certified centre of excellence for OC treatment. Patients were treated between 01/2011–12/2022. BRCA1/2 was mainly analysed in germline. Location of BRCA mutations at DNA-BS were classified as earlier published. Results In the respective interval, 1765 patients were treated, 326 (18.5%) with FIGO I-II and 1429 (81.5%) FIGO III-IV stage disease. There were significant differences (p<0.001) in histological differentiation between early and advanced OC: high-grade serous (37.4%/85.5%), high-grade endometrioid (5.5%/1.3%), low-grade serous (3.1%/6.8%), low-grade endometrioid (21.5%/0.8%), mucinous (13.2%/0.4%), others (19.3%/5.1%). BRCA mutation status was known in 51.8% of early stage and 62.2% in advanced stage OC. There were significant differences of BRCA1/2 mutation frequencies between all patients with early (8.9%/2.4%) and advanced (13.6%/6.9%) stage disease (p=0.03). However, in patients with high-grade histologies, no differences (p=0.6) of BRCA1/2 mutation frequency between early (17.7%/3.8%) and advanced stage (15.3%/7.7%) OC were observed, respectively. There were no differences of the frequencies of BRCA1 (p=0.7) or BRCA 2 (p=1.0) mutations at the DNA-BS between early and advanced stage OC. Conclusion BRCA1/2 frequency differences between patients with early and advanced stage OC are due to histological disparities. There are no hints that tumor biology defined by BRCA is different between early and advanced high-grade OC. Disclosures No conflicts of interest regarding this abtract.

Objective Nearly 30% of unselected endometrial cancer (EC) are mismatch repair deficient (MMRd).The majority resulting from epigenetic changes due to MLH1 promoter hypermethylation (MLH1-PM) and only a fraction from mutations in the Lynch genes (MLH1/MSH2/MSH6/PMS2).

Objectives To evaluate the prevalence and clinical impact of deleterious germline mutations in EOC patients.

Background National/international guidelines recommend germline genetic testing for BRCA1/2 and other ovarian cancer genes for women with epithelial-ovarian cancer (EOC). Our aim was to evaluate the prevalence and clinical characterization of patients harboring concurrent multiple deleterious mutations (CMDM).

Objective Next generation sequencing (NGS) allows simultaneous sequencing of multiple cancer risk genes including BRCA1/2. However, the clinical features of EOC patients with a gene variant of uncertain significance (VUS) are unclear. Our aim was to evaluate the prevalence and clinical outcome of patients with a VUS result and EOC.

Hintergrund Adulte Granulosazelltumore (AGCT) gehören mit < 5 % zu den seltenen malignen Ovarialtumoren. Wenngleich der Großteil bei Erstdiagnose im FIGO-Stadium I diagnostiziert wird, treten in ca. 25% der Fälle Rezidive auf. Die operative Komplettresektion spielt eine entscheidende Rolle in der Rezidivtherapie. Ziel dieser Arbeit ist die Charakterisierung der Rezidivoperation bei AGCT.

Objectives To evaluate the prevalence of LARS-like symptoms in primary diagnosed ovarian cancer (OC) and the effect of surgery regarding recto-sigmoid resection.

Background Many gynecologic cancers fulfill the criteria of a rare tumor with an annual incidence of <6 per 100,000 women. As these tumor entities are difficult to treat, specialized knowledge and skills are necessary.

Hintergrund Borderline-Tumore (BOT) gelten als seltene Tumore des Ovars und treten häufig in jüngerem Alter auf, weshalb einer Fertilitätserhaltenden Therapie (FSS) große Bedeutung zukommt.

Introduction/Background The aim of the study was to assess the oncological outcomes of cytoreductive surgery in FIGO IV and recurrent endometrial cancer. Methodology This is a retrospective, observational, single-center cohort study including patients with endometrial cancer FIGO IV stage disease undergoing primary cytoreductive surgery and recurrent endometrial cancer treated with secondary cytoreductive surgery between January 1999 and April 2022. Results 115 patients were included in the present study. In the 53 patients with primary FIGO IV disease complete macroscopic resection was achieved in 42/53 (79.2%) cases. Median OS in these patients was 35 months and median PFS was 15 months. Sixty-two patients had cytoreductive surgery for relapsed endometrial cancer and complete macroscopic resection was achieved in 82.2%. Median OS in this population was 28 months and median PFS was 8.2 months. Patients with complete macroscopic resection showed longer progression-free survival (PFS) and overall survival (OS) compared to those with residual disease (PFS: 15.1 vs 12.9 months; p=0,189; OS: 32.4 vs 17 months; p=0,130). Median OS was 44.6 months (95 % CI 24,6- 64,6 months) in endometrioid subtype (72/115 pts) and 27.4 months (95 %CI 7.2–47.6 months) in other histotypes (p=0.114). Major complications (>Clavien Dindo IIIB) were noted in 10/115 pts (8.7%), mortality rate was 0.9%. Conclusion Complete macroscopic resection is feasible in selected patients with FIGO IV and relapsed endometrial cancer with an acceptable morbidity, and seemed to be related to superior outcome. However, its impact on prognosis should be further evaluated.

Objective To investigate the impact of substage, histological subtype and other prognostic factors for FIGO stage I epithelial ovarian cancer (EOC) on long-term survival.

Introduction/Background* Adult granulosa cell tumors (aGCT) represent less than 5% of all ovarian malignancies. The aim of this study was to analyze clinical and histopathological parameters and their impact on recurrence, progression-free- (PFS) and overall survival (OS). Methodology Patients diagnosed with primary aGCT and treated in three international referral centers were included in the study. The following variables were anonymously exported from the prospective database of each clinic for further analysis: patient's age at diagnosis, stage, chemo-, radiation, or hormonal therapy, surgery for primary site, type of restaging surgery, lymph nodes dissected, follow-up months, PFS, and OS. Descriptive statistical analysis regarding tumor and treatment characteristics was performed. Survival analyses included Kaplan-Meier functions and Cox proportional hazard ratios (HR). Result(s)* The total study cohort included 168 patients with primary aGCT, which were treated surgically. Median age was 50 years (range 13-82). 54.2% (n=91) of patients had FIGO stage IA, 26.8% (n=45) were stage IC, and 17.8% (n=32) had FIGO stage II-IV. In total 66.7% (n=112) of patients underwent surgical restaging procedure of whom 11.9% (n=20) were up-staged. A median laparotomy was performed in 70.8% (n=119) of patients. Adjuvant chemotherapy was administered to 11.3% of patients (n=19) and one patient received endocrine therapy. After a median follow-up of 61 months, 10.7% (n=18) had recurrent disease and 4.8% (n=8) of patients died from the disease. Overall five-year PFS was 86.1% and estimated OS was 95.7%. Survival was worse for patients with advanced stages (FIGO IA/B vs. IC, HR = 5.09; 95% confidence interval [CI]: 1.53-16.9; FIGO IA/B vs. II-IV, HR=5.62; 95% CI: 1.58-19.9) and for patients who underwent adjuvant chemotherapy (HR=9.15; 95% CI: 3.62-23.1). Conclusion* Prognosis of patients with primary aGCT is mainly determined by FIGO-Stage. The outcome of FIGO stage IC is comparable to advanced stages and a significant number of patients were up-staged. The role of adjuvant chemotherapy remains unclear and should be investigated in future studies.