RT Journal Article SR Electronic T1 1298 Evaluation of the peritoneal surface disease severity score (PSDSS) in ovarian cancer patients undergoing cytoreductive surgery and HIPEC: two pathogenetic types based study JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A421 OP A422 DO 10.1136/ijgc-2024-ESGO.826 VO 34 IS Suppl 1 A1 Yarema, Roman A1 Volodko, Nataliya A1 Petronchak, Orest A1 Huley, Roman A1 Ohorchak, Myron A1 Mylyan, Yuriy YR 2024 UL http://ijgc.bmj.com/content/34/Suppl_1/A421.2.abstract AB Introduction/Background Clinical experience suggests that cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) play an important role in the management of ovarian cancer. In order to improve patient selection, the peritoneal surface disease severity score (PSDSS) was previously introduced for use in colorectal cancer patients. However, almost no data exist regarding the utility of the PSDSS index in ovarian cancer patients.Methodology A retrospective study of the effectiveness of CRS and HIPEC was carried out in 59 patients with ovarian cancer. The PSDSS was based on three criteria: symptoms, extent of peritoneal dissemination, and primary tumor structure as assessed by histology and biomarker expression. The PSDSS evaluation was performed in accordance with the original algorithm based on differentiating the ovarian cancer patients into two pathogenetic types depending on their histological and immunohistochemical results. The PSDSS stages scored from I to IV based scores for each of the three clinicopathological parameters (PSDSS Stage I: ≤ 3 points; PSDSS Stage II: 4–6 points; PSDSS Stage III: 7–10 points, and PSDSS Stage IV: ≥ 11 points).Results The overall survival time for patients with ovarian cancer in PSDSS Stage I was 48 ± 25.3 months. For PSDSS Stage II, the survival time was 26.5 ± 4.7 months. For PSDSS Stage III, it was 15.5 ± 4 months, and for PSDSS Stage IV, it was 6 ± 4.3 months. A multivariate analysis showed that the PSDSS stage was the only independent survival predictor.Conclusion These data demonstrate that a PSDSS based on two pathogenetic types may be useful for predicting survival outcomes in ovarian cancer patients treated with CRS/HIPEC.Disclosures The authors have no conflict of interest.Abstract 1298 Figure 1