First report on the characterization of public and private patients with ovarian cancer in Chile.

e17588 Background: Ovarian cancer (OC) is considered the most aggressive gynecologic cancer. In Chile, the incidence and mortality rate of OC are increasing, with OC being the 8 th most common cause of death from cancer in females. Understanding real-world patients’ characteristics, treatment patterns, and clinical evolution is relevant to improve care and estimate disease burden, especially since OC was included in the national formulary in 2013, ensuring coverage for diagnosis and treatment. The aim of this study was to describe the characteristics of patients with OC diagnosed before and after inclusion of OC in the national public health program in Chile. Methods: This is a retrospective, observational study conducted using medical chart data from the oncology unit of two centers in Santiago, Chile: Pontifical Catholic University Cancer Center (UC) and Sótero del Río Hospital (SRH). UC is attended by both public and private patients, whereas SRH is only attended by public patients. Patients aged ≥18 years with a confirmed OC diagnosis between 2010 and 2024 were included. Demographic, clinical, treatment, and BRCA and homologous recombination (HR) testing data were collected and described using SPSS and R. Continuous variables are reported as mean and standard deviation (SD), and categorical variables as frequency and proportions. Results: In total, 288 patients were included in this study: 205 (71.2%) from UC and 83 (28.8%) from SRH. At diagnosis, patients had a mean age of 58.5 (SD 10.9) years and 226 (78.5%) patients had ascites, with similar proportions between centers. Obesity by body mass index was reported in 46 (17.5%) patients (UC: n=24 [12.6%]; SRH: n=22 [30.6%]), and 230 (79.9%) patients were diagnosed at FIGO (International Federation of Gynecology and Obstetrics) stage III/IV disease (UC: n=169 [82.4%]; SRH: n=61 [73.5%]). High-grade serous histology was identified in 241 (83.7%) patients (UC: n=176 [85.9%]; SRH: n=65 [78.3%]). Only the UC reported patients had BRCA (n=74 [36.1%]) and HR testing (n=16 [7.8%]). BRCA mutations were found in 43.2% (n=32) of those tested, whereas 56.3% (n=9) of those HR tested were identified as HR deficient. Of the patients who underwent surgery, 162 (84.8%) achieved R0 cytoreduction (with similar proportions between centers). Neoadjuvant chemotherapy was administered in 63 (22.7%) patients who were treated with chemotherapy (UC: n=41 [20.9%]; SRH: n=22 [27.2%]). Conclusions: Patients with OC were diagnosed with advanced disease stages. Few patients underwent BRCA and HR testing, but a high incidence of BRCA mutations or HR deficiency was found. Funding: GSK (219517).