[Application of CA125 elimination rate constant K score in prognostic forecast of patients undergoing interval debulking surgery for high grade serous ovarian cancer].

Objective: To investigate the predictive value of the cancer antigen 125 (CA₁₂₅) elimination rate constant K (KELIM) score for no visible residual disease (R0) and prognosis in high-grade serous ovarian carcinoma (HGSOC) patients undergoing neoadjuvant chemotherapy (NACT)+interval debulking surgery (IDS). Methods: A retrospective analysis was conducted on 78 HGSOC patients treated with NACT+IDS at Beijing Hospital, from June 2014 to June 2024. The KELIM score was calculated, and its predictive value for R0 resection, chemotherapy response score (CRS), platinum-free interval (PFI), progression-free survival (PFS) time, and overall survival (OS) time was analyzed. Results: (1) The mean age at diagnosis was (61.9±9.9) years. The mean KELIM score was 1.1±0.4, with 44 patients having KELIM score≥1 and 34 having KELIM score <1. (2) Patients with KELIM score ≥1 had significantly higher rates of R0 resection (84% vs 56%; P=0.006), CRS3 grading (41% vs 0; P<0.001), and PFI ≥6 months (84% vs 53%; P=0.04) compared to those with KELIM score <1. Additionally, the median PFS time (18.7 vs 13.2 months; P<0.001) and OS time (34.8 vs 29.9 months; P=0.007) were significantly longer in the KELIM score ≥1 group. Chemosensitivity: patients with PFI <6 months had a significantly lower median KELIM score than those with PFI ≥6 months (0.8 vs 1.2; P=0.005). Surgical outcome: patients achieving R0 resection had a significantly higher median KELIM score than those without R0 (1.2 vs 0.7; P<0.001). (3) Univariate analysis identified non-R0 resection, CRS3 grading, lack of poly adenosine diphosphate ribose polymerase (PARP) inhibitor maintenance therapy, and KELIM score <1 as significant risk factors for OS time (all P<0.05). Multivariate analysis confirmed non-R0 resection (HR=3.78,95%CI: 1.13-12.66; P=0.031), no PARP inhibitor maintenance (HR=7.41,95%CI:1.82-30.15; P=0.005), and KELIM score <1 (HR=5.14,95%CI:1.41-18.72; P=0.013) as independent risk factors for OS time. Conclusions: The KELIM score may serve as a predictive marker for chemosensitivity, R0 resection, PFS time, and OS time in HGSOC patients undergoing NACT+IDS. KELIM score<1 is an independent risk factor for OS.