Lymphopenia association with whole-brain radiotherapy and its effects on clinical outcomes of patients with brain metastases

Abstract

Abstract Introduction: Radiotherapy has emerged as a primary treatment modality for brain metastases, and there is increasing awareness of its potential side effects, such as lymphopenia. Therefore, the objective of this study was to establish the association between WBRT and the development of lymphopenia in patients with brain metastases undergoing brain radiotherapy (RT), along with evaluating the corresponding clinical outcomes. Methods: The study included a total of 116 patients with brain metastases undergoing brain radiotherapy, and collected the absolute lymphocyte count (ALC) within 2 weeks before brain radiotherapy (pre-radiotherapy, pre-RT), as well as at 1 and 2 months after completing RT (post-RT). Univariate and multivariate analyses were performed to identify associations between radiation modality and post-RT ALC. The relationships between post-RT ALC and overall survival were evaluated with Kaplan-Meier analysis and a multivariate Cox regression model. Results: At 1 month post-RT, the median ALC definitely decreased. At 2 months post-RT, the ALC gradually rose but not to the pre-RT ALC. The multivariate analysis identified WBRT and lower pre-RT ALC as independent risk factors associated with the decrease in post-RT ALC at 1 month. It also revealed more than 4 brain metastases, G3-4 lymphopenia at 1 month and lower post-RT ALC at 2 months exhibited significantly worse prognosis regardless of the radiation modality. However, there is indeed an independent correlation between radiation modality and the outcome of intracranial progression-free survival (PFS). Conclusions: To approach the feasibility and reasonableness of treatment, clinicians should carefully consider various factors to achieve long-term survival of patients.