# Post-Chemoradiation Lymphopenia and Baseline Eosinophil Counts as Prognostic Markers in Glioblastoma

## TL;DR

The study found that low lymphocyte counts after treatment and high baseline eosinophil counts may predict survival in glioblastoma patients.

## Contribution

The novel contribution is identifying baseline eosinophil counts and post-treatment lymphopenia as potential prognostic markers in glioblastoma.

## Key findings

- Baseline absolute eosinophil count (AEC) independently correlates with improved overall survival in glioblastoma patients.
- Post-chemoradiation lymphopenia (ALC < 0.75 ×10³/μL) is associated with shorter survival on univariate analysis but not in multivariable models.
- Lymphocyte-sparing treatment strategies and validation of these markers are recommended for future research.

## Abstract

To evaluate whether post-treatment lymphopenia and white-cell differentials predict overall survival (OS) in glioblastoma (GBM).

We retrospectively analyzed 93 GBM patients treated with standard surgery, radiotherapy (60 Gy in 30 fractions), and temozolomide. Clinical data (age, Karnofsky performance status, extent of resection, MGMT methylation, corticosteroid use, dose metrics) and hematologic indices (absolute lymphocyte count (ALC), neutrophil-to-lymphocyte ratio (NLR), absolute eosinophil (AEC) and basophil counts, etc.) were collected at baseline and up to 3 months post-chemoradiation.

Median OS in our cohort was 24.7 months (95% CI, 20.8–35.0). On univariate analysis, ALC < 0.75 ×103/μL at 3 months was associated with shorter OS (HR 1.88; p = 0.042), and higher AEC correlated with improved OS at baseline (HR 0.71; p = 0.022) and at 1–2 months (HR 0.44 and 0.57; p = 0.046 and 0.016). In the combined multivariable model—controlling for age, extent of resection, MGMT status, steroid usage and dose metrics—baseline AEC remained independently prognostic (aHR 0.57; p = 0.016), whereas the association for 3-month ALC < 0.75 ×103/μL attenuated (aHR 1.27; p = 0.49).

Baseline eosinophils were independently associated with improved survival, while post-treatment lymphopenia was adverse only on univariate analysis. Such findings highlight the importance of host immunity and baseline eosinophils as a potential prognostic marker of OS in GBM and warrant larger, prospective studies on lymphocyte-sparing treatment strategies and prognostic marker validation.