NTCP Modeling of Visual Processing Speed Impairment and Related Factors Following Radiotherapy in Patients with Brain...

Area of Science:

• Radiation Oncology
• Neuro-oncology
• Medical Physics

Background:

• Brain metastases frequently cause neurocognitive deficits, including impaired visual processing speed (VPS).
• Whole-brain radiotherapy (WBRT) is a common treatment for brain metastases.
• Assessing the risk of VPS impairment is crucial for optimizing WBRT.

Purpose of the Study:

• To develop a Normal Tissue Complication Probability (NTCP) model for VPS impairment after WBRT.
• To identify dosimetric and clinical predictors of VPS impairment.
• To provide a tool for predicting and potentially mitigating radiation-induced neurotoxicity.

Main Methods:

• Retrospective analysis of 18 patients treated with WBRT.
• Hippocampal dose-volume histograms (DVHs) were generated.
• NTCP models were calculated using the Lyman model and multivariable logistic regression.

Main Results:

• Visual processing speed (VPS) impairment was observed in 33.3% of patients.
• The Lyman-Kutcher-Burman (LKB) model yielded TD50 of 38.43 Gy.
• Multivariable logistic regression demonstrated superior predictive performance over the Lyman model, though no specific variables were significant predictors (P > 0.05).

Conclusions:

• A predictive model for radiation-induced visual processing speed (VPS) impairment was successfully developed.
• The study suggests that limiting hippocampal radiation dose to under 20 Gy could maintain Normal Tissue Complication Probability (NTCP) below 25%.
• Further research with larger cohorts is warranted to validate these findings and refine predictive models.