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Effects of radiobiological 5Rs on carbon-ion radiotherapy for stage I non-small cell lung cancer
https://repo.qst.go.jp/records/2002751
https://repo.qst.go.jp/records/2002751defdf748-44ef-40b6-bff1-e6e3181e48fb
| アイテムタイプ | 会議発表用資料 / Presentation(1) | |||||||
|---|---|---|---|---|---|---|---|---|
| 公開日 | 2026-02-11 | |||||||
| タイトル | ||||||||
| タイトル | Effects of radiobiological 5Rs on carbon-ion radiotherapy for stage I non-small cell lung cancer | |||||||
| 言語 | en | |||||||
| 言語 | ||||||||
| 言語 | eng | |||||||
| 資源タイプ | ||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||||
| 資源タイプ | conference presentation | |||||||
| 著者 |
Inaniwa Taku
× Inaniwa Taku
|
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| 抄録 | ||||||||
| 内容記述 | Background and aims:A single-fractionated carbon-ion radiotherapy for stage I non-small cell lung cancer (NSCLC) was started in 2003 with the prescribed RBE-weighted dose of 28 Gy according to the clinical experiences of 18-, 9-, and 4-fraction treatments. The prescribed dose was gradually increased up to 50 Gy to control the NSCLC, which is unexpectedly higher than initially estimated. The purpose of this study was to investigate the effects of the radiobiological 5Rs, radiosensitivity, repopulation, repair, redistribution, and reoxygenation, on the 3-year tumor control probability (TCP) of patients with stage I NSCLC treated with carbon-ion radiotherapy.Methods:A meta-analysis of published clinical data of 233 NSCLC patients treated by carbon-ion radiotherapy under 18-, 9-, 4-, and single-fraction schedules was conducted. The linear-quadratic (LQ)-based cell-survival model incorporating the radiobiological 5Rs was developed to reproduce the clinical TCP data. Redistribution and reoxygenation were regarded together as a single phenomenon and termed “resensitization” in the model. The optimum interval time between fractions was investigated for each fraction schedule using the determined model parameters.Results:The clinical TCP data for 18-, 9-, and 4-fraction schedules were reasonably reproduced by the model without the resensitization effect, whereas its incorporation was essential to reproduce the TCP data for all fraction schedules including the single fraction. The curative dose for the single-fraction schedule was estimated to be 49.0 Gy, which corresponds to the clinically adopted dose prescription of 50.0 Gy. For 18-, 9-, and 4-fraction schedules, a 2-to-3-day interval is required to maximize the resensitization effect during the time interval. In contrast, the single-fraction schedule cannot benefit from the resensitization effect, and the shorter treatment time is preferable to reduce the effect of sub-lethal damage repair during the treatment.Conclusions:The LQ-based cell-survival model incorporating the radiobiological 5Rs was developed and used to evaluate the clinical results of NSCLC patients treated with hypo-fractionated carbon-ion radiotherapy. The incorporation of the resensitization into the cell-survival model improves the reproducibility to the clinical TCP data. A shorter treatment time is preferable in the single-fraction schedule, while a 2-to-3-day interval between fractions is preferable in the multi-fraction schedules for effective treatments. | |||||||
| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||||
| 内容記述 | PTCOG63 | |||||||
| 発表年月日 | ||||||||
| 日付 | 2025-06-06 | |||||||
