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

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.

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.

Retrospective cohort study.

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.

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).

LMR may hold prognostic value for SFTs, though further validation in larger, multi-institutional cohorts is warranted.