Long-term intelligence after high-dose radiotherapy to the primary site versus chemotherapy and whole-ventricle radiotherapy in patients with germinoma

Abstract

Background: Until 1995, patients with newly diagnosed germinoma received 40–60 Gy of radiation to the primary site with or without chemotherapy (regimen A). After 2000, treatment shifted to chemotherapy followed by 24 Gy of whole-ventricle radiation therapy (WVRT) (regimen B). This study compares long-term intelligence outcomes between the two treatment regimens. Methods: This retrospective analysis included 151 patients diagnosed with germinoma between 1983 and 2021. Intelligence was assessed using the Wechsler Adult Intelligence Scale (revised or 3rd edition) and the Wechsler Intelligence Scale for Children (3rd edition). Patient backgrounds were also collected. Results: A total of 55 and 69 patients were treated with regimens A and B, respectively. The number of patients who underwent at least one longitudinal neurocognitive assessment was 35 and 29 for regimen A and 53 and 22 for regimen B, respectively. The median interval from initial treatment to the last neurocognitive assessment was 120 months. In the longitudinal intelligence assessments, the median intervals were 58 months from treatment to the first evaluation and 83 months from the first to the final assessment. Full-Scale Intelligence Quotient (FSIQ) scores declined in regimen A but were maintained in regimen B according to analysis of covariates and generalized linear mixed model analysis. Conclusion: Chemotherapy followed by 24 Gy of WVRT appears to be associated with a smaller decline in FSIQ over a long-term follow-up.