Prognostic Significance of Complete Blood Count-Derived Inflammatory Biomarkers in Patients with Small Cell Neuroendocrine Carcinoma of the Cervix

Background: Small cell neuroendocrine carcinoma of the cervix (SCNEC) is a rare and highly aggressive malignancy with limited prognostic biomarkers available for clinical use. Inflammatory markers derived from complete blood count (CBC) have been shown to reflect the systemic immune response and tumor progression in various cancers, but their prognostic value in SCNEC remains unclear. Methods: We retrospectively analyzed clinical data from patients diagnosed with SCNEC between 2004 and 2024 across two centers. Internal validation was performed by dividing patients into training and test cohorts. Cox regression analyses and Kaplan–Meier survival analyses were used to evaluate prognostic factors and treatment outcomes. Inverse probability of treatment weighting (IPTW) was applied to reduce baseline imbalances. Patients were randomly divided into training and test cohorts. A nomogram was constructed to predict 3-year and 5-year progression-free survival (PFS) with performance evaluated using receiver operating characteristic (ROC) curves, calibration plots, and decision curve analysis (DCA). Results: 196 participants were included in the study. Age, FIGO 2018 stage, surgery, neutrophil-to-lymphocyte ratio (NLR), and monocyte-to-lymphocyte ratio (MLR) were independently associated with PFS. High MLR (>0.19) was significantly linked to shorter PFS. After IPTW adjustment, the protective effect of low MLR on PFS remained significant (p = 0.029). The constructed nomogram demonstrated excellent predictive performance, with area under the curve (AUC) values of 0.799 and 0.787 for 3-year and 5-year PFS in the training cohort, and 0.802 for endpoints in the test cohort. Conclusions: MLR was identified as an independent prognostic biomarker for PFS in SCNEC, with potential value in risk stratification and personalized treatment strategies. Additionally, we developed a reliable nomogram that accurately predicts 3-year and 5-year PFS, serving as a practical tool for individualized prognosis and clinical decision-making.