Clinical importance of ADC in the prediction of 125I in the treatment for gliomas

Objectives: To determine whether the minimum apparent diffusion coefficient (minADC) value can stratify survival in patients with glioma before 125I brachytherapy. Methods: The study was approved by the Institutional Review Board, and the requirement for informed consent was waived. Twenty-three patients (16 male, 7 female; median age, 48 years) with high-grade glioma (HGG) (n=9) or recurrence after multimodal treatment (n=14) were included in this study. minADC values were obtained before 125I implantation. Overall survival (OS) and progression-free survival (PFS) were analyzed with Cox proportional hazards regression models and the Kaplan-Meier method with the log-rank test. Results: For 125I-treated patients, the hazard ratio for OS in patients with ADC≥1.0*10^-3 mm2·sec-1 (high minADC) versus ADC<1.0*10^-3 mm2·sec-1 (low minADC) was 0.220 (95% confidence interval: 0.066, 0.735). The median OS was 12 months for patients with high minADC values and 6.0 months for those with low minADC values, and the differences were significant (p=0.032). The median PFS was 12 months for patients with high minADC values and 4 months for those with low minADC values. Significant differences were found in the long-rank test (p=0.013). The multivariate analysis results showed that minADC pre-125I implantation was an independent predictor of OS and PFS in patients receiving 125I brachytherapy. Conclusions: Pre-125I implantation ADC analysis can stratify prognosis in 125I-treated patients with glioma, which may aid in choosing a suitable therapy for glioma patients.