[Niigata University of Health and Welfare] Radiosensitivity to Glioma, a Type of Brain Tumor, Tends Not to Change Significantly Even After Recurrence

A research group led by Lecturer Hisashi Nakano of the Department of Health Data Science, Niigata University of Health and Welfare (NSG Group), and Lecturer Takehiro Shiinoki of the Department of Radiation Oncology, Yamaguchi University Hospital, has revealed through a large-scale analysis of 214 patient data that the "radiosensitivity index" (RSI score: Radiosensitivity Index), which predicts the "ease of radiation effectiveness" that differs among patients in radiation therapy for glioma, a type of brain tumor, tends not to change significantly overall even after recurrence.

This research outcome was published in the international academic journal "Journal of Neuro-Oncology" on April 15, 2026.

About the Research

[Research Overview]

Radiation therapy plays a central role in the treatment of glioma, a type of brain tumor, but it is known that there are significant individual differences in radiosensitivity among patients. To date, an index (RSI score: Radiosensitivity Index) that quantifies radiosensitivity from the function of 10 genes has been developed and has attracted attention. On the other hand, it is known that the nature of cancer changes significantly upon recurrence of glioma, and it has not been clarified whether "the score measured initially can be used in the same way after recurrence." This point has been one of the important issues in promoting personalized medicine.

In this study, we combined an international large-scale database (214 patient data) with single-cell analysis (a technology that individually analyzes each cell) to analyze approximately 7,000 malignant tumor cells in detail. As a result, it was revealed that the score indicating radiosensitivity tends not to change significantly overall even after recurrence. This finding suggests that even when re-biopsy of the tumor is difficult at recurrence, data from the initial surgery may serve as reference information when considering treatment strategies. It is expected that further validation will contribute to the selection of personalized radiation therapy for each patient.

Figure 1 Comparison of "Radiosensitivity Score (RSI Score)" at initial treatment and recurrence (214 patient data)

Figure 2 "Radiosensitivity Score" by cancer cell type (individual analysis of approximately 7,000 cells)

[Key Points of Research Results]

・It was revealed through a large-scale analysis of 214 patient data that the RSI score, which indicates the radiosensitivity of glioma, a type of brain tumor, does not change significantly overall from the initial treatment to recurrence. This result suggests that even when re-biopsy of tumor tissue is difficult at recurrence, data from the initial surgery may serve as reference information when considering treatment strategies.

・As a result of detailed analysis of the relationship between score changes and survival period, the seemingly observed association was due to the influence of IDH gene (isocitrate dehydrogenase gene) mutation, which is known as a representative prognostic factor for glioma, and the score change itself was not confirmed to be an independent prognostic factor in this analysis. This finding reconfirms the extreme importance of evaluating IDH gene mutation in predicting the prognosis of glioma.

[Researcher's Comment]

◆Lecturer Hisashi Nakano, Department of Health Data Science In radiation therapy for brain tumors, when considering whether to perform radiation therapy again (re-irradiation) at recurrence, whether the radiosensitivity of the tumor has changed from the initial treatment is an important clinical question. This time, targeting glioma, a type of brain tumor, we systematically analyzed an international large-scale database (214 patient data) on an unprecedented scale, and were able to show that the predictive score for radiosensitivity tends not to change significantly overall even after recurrence. On the other hand, it was not confirmed that this score change alone could independently predict the patient's prognosis (course after treatment), and its limitations were also clarified. Going forward, we believe it is necessary to advance experimental validation and develop new radiosensitivity indices suitable for single-cell level analysis.

[Original Paper Information]

Nakano Hisashi and Shiinoki Takehiro. Radiosensitivity index stability across glioma progression: a longitudinal bulk and single-cell analysis. Journal of Neuro-Oncology. 2026;177:107. DOI: 10.1007/s11060-026-05570-y

URL: https://link.springer.com/article/10.1007/s11060-026-05570-y

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