Preoperative Pan-Immune-Inflammation Value for the Differential Diagnosis and Prognostic Assessment of Ovarian Tumors: A Retrospective Cohort Study

Background/Objectives: Preoperative differentiation of benign, borderline, and malignant ovarian tumors remains challenging. The pan-immune-inflammation value (PIV), a composite inflammation-based biomarker derived from routine blood counts, may contribute to ovarian tumor characterization. This study aimed to evaluate the diagnostic and prognostic significance of PIV in ovarian tumors. Methods: This retrospective single-center cohort study included 316 patients with histopathologically confirmed ovarian tumors classified as benign (n = 139), borderline (n = 61), or malignant (n = 116). Preoperative inflammatory indices were calculated from peripheral blood samples obtained within 24 h before surgery. Diagnostic performance was assessed using receiver operating characteristic (ROC) curve analysis and multivariable logistic regression. Progression-free survival (PFS) and overall survival (OS) were evaluated in malignant cases with available follow-up. Results: Inflammatory indices increased significantly from benign to borderline and malignant tumors (p < 0.001 for all). Among inflammatory markers, PIV demonstrated the highest diagnostic performance, with an area under the curve (AUC) of 0.852 (95% CI 0.808–0.893), sensitivity of 75.0%, and specificity of 80.5%. CA-125 demonstrated the highest overall diagnostic accuracy (AUC 0.978, 95% CI 0.961–0.991). Pairwise ROC analyses showed consistent discriminatory performance of PIV across ovarian tumor comparisons. In multivariable analysis, age, tumor size, ln(CA-125), and ln(PIV) were independently associated with malignancy (all p < 0.05). The combined CA-125 + PIV model demonstrated a statistically significant but modest improvement in diagnostic performance compared with CA-125 alone. During a median follow-up of 26.9 months (IQR 22.2–32.5), PIV was not significantly associated with PFS or OS. Conclusions: PIV demonstrated the highest diagnostic performance among evaluated inflammatory indices and may provide complementary information for preoperative epithelial ovarian tumor assessment. However, CA-125 remained the most accurate standalone biomarker, and the prognostic value of PIV appeared limited.