Blood immune profiling predicts surgical anatomy and facial nerve outcome in Vestibular Schwannoma.

BACKGROUND

Surgical resection of vestibular schwannoma (VS) is frequently complicated by unpredictable tumor fibrosis and adhesion to the facial nerve and brainstem, yet validated preoperative blood-based biomarkers for these intraoperative features are lacking. We tested whether peripheral blood immune profiles predict the intraoperative surgical anatomy of VS.

METHODS

In a retrospective cohort of 342 VS patients undergoing microsurgical resection via the retrosigmoid approach, high-dimensional peripheral blood flow cytometry quantified T, B, and NK cell subsets, memory/activation status, and PD-1 exhaustion markers, alongside routine hematological parameters. Multivariable logistic regression models adjusted for age, sex, and tumor size were constructed for four endpoints: tumor texture, facial nerve adhesion, brainstem adhesion, and postoperative facial nerve function.

RESULTS

Each 1-SD increase in central memory CD8+ T-cell (Tcm CD8+) levels was associated with lower odds of hard, fibrotic tumor texture (OR = 0.68, 95% CI 0.52-0.88, p = 0.004). Brainstem adhesion was associated with elevated NK cells (OR = 1.50, p = 0.023), whereas each 1-SD increase in Tcm CD8+ levels was associated with lower odds of adhesion (OR = 0.64, p = 0.018), yielding an apparent AUC of 0.80 (bootstrap-corrected 0.76). Severe facial nerve adhesion was associated with elevated platelets (OR = 1.59, p = 0.021), whereas each 1-SD increase in TEMRA CD4+ levels was associated with lower odds of severe adhesion (OR = 0.56, p = 0.006). Higher preoperative CD8+ T-cell levels were associated with lower odds of poor facial nerve function (OR = 0.58, p = 0.015). A combined NK-Tcm CD8+ risk score stratified brainstem adhesion from 8.8% to 24.6% across three tiers (P_trend = 0.002), with adequate model calibration (Hosmer-Lemeshow p = 0.795).

CONCLUSION

Systemic immune profiles were associated with VS surgical anatomy and postoperative facial nerve outcome. These exploratory biomarkers require prospective external validation before they can be considered for clinical risk stratification.