Clinical and hematological indices as prognosticators in localized solitary fibrous tumors: A retrospective study.

BACKGROUND: Solitary fibrous tumors (SFTs) are rare fibroblastic neoplasms for which prognostication is challenging. Peripheral hematological indices such as lymphocyte-monocyte ratio (LMR) and neutrophil-lymphocyte ratio (NLR) have demonstrated prognostic value in various malignancies but remain incompletely characterized in localized SFTs. OBJECTIVES: This study aimed to investigate clinicopathological factors and peripheral blood counts as predictors of survival outcomes in patients with SFT; and to explore their relationship with intratumoral gene expression profiles. DESIGN: Retrospective cohort study. METHODS: We analyzed patients with localized SFT managed at the National Cancer Centre Singapore (n = 77). Cut-offs for indices were derived from prior studies, and survival outcomes were analyzed using the Kaplan-Meier method and Cox proportional-hazards regression. Subgroup analysis with the NanoString PanCancer IO360 panel (n = 9) was done to explore associations between peripheral LMR and intratumoral immune-oncologic signals. RESULTS: Median age at diagnosis was 55.7 years (range: 12.7 to 86.5 years) with a median follow-up time of 10.1 years. Low LMR (≤ 2.4) was observed in 14 patients (18.2%) and was significantly associated with poorer overall survival (OS) (HR 6.73, 95% CI 1.65 - 27.4, p = 0.0078) alongside older age (> 65 years) and absence of curative surgery. Low LMR was also associated with poorer metastatic-free survival (MFS) (HR 5.11, 95% CI 1.48 - 17.70, p = 0.0101) and trended toward worse event-free survival (EFS) (HR 2.76, 95% CI 0.92 - 8.31, p = 0.071). LMR-low was significantly correlated with lower lymphocyte counts (median: 1.23 vs 1.94×109/L; p < 0.0001) and higher monocyte counts (median: 0.66 vs 0.51×109/L; p = 0.0041). Using NanoString analysis, LMR was negatively correlated with intratumoral cytokine and chemokine signaling pathway scores (rho = -0.733, p = 0.0246), mast cell scores (rho = -0.700, p = 0.0358) and CD8 T cells (rho = -0.667, p = 0.0499). CONCLUSION: LMR may hold prognostic value for SFTs, though further validation in larger, multi-institutional cohorts is warranted.