TY - JOUR T1 - Unresectable Chondrosarcomas Treated With Carbon Ion Radiotherapy: Relationship Between Dose-averaged Linear Energy Transfer and Local Recurrence JF - Anticancer Research JO - Anticancer Res SP - 6429 LP - 6435 DO - 10.21873/anticanres.14664 VL - 40 IS - 11 AU - SHINNOSUKE MATSUMOTO AU - SUNG HYUN LEE AU - REIKO IMAI AU - TAKU INANIWA AU - NARUHIRO MATSUFUJI AU - MAI FUKAHORI AU - RYOSUKE KOHNO AU - SHUNSUKE YONAI AU - NORIYUKI OKONOGI AU - SHIGERU YAMADA AU - NOBUYUKI KANEMATSU Y1 - 2020/11/01 UR - http://ar.iiarjournals.org/content/40/11/6429.abstract N2 - Background/Aim: The local control rate of chondrosarcomas treated with carbon-ion radiotherapy (CIRT) worsens as tumour size increases, possibly because of the intra-tumoural linear energy transfer (LET) distribution. This study aimed to evaluate the relationship between local recurrence and intra-tumoural LET distribution in chondrosarcomas treated with CIRT. Patients and Methods: Thirty patients treated with CIRT for grade 2 chondrosarcoma were included. Dose-averaged LET (LETd) distribution was calculated by the treatment planning system, and the relationship between LETd distribution in the planning tumour volume (PTV) and local control was evaluated. Results: The mean LETd value in PTV was similar between cases with and without recurrence. Recurrence was not observed in cases where the effective minimum LETd value exceeded 40 keV/μm. Conclusion: LETd distribution in PTV is associated with local control in chondrosarcomas and patients treated with ion beams of higher LETd may have an improved local control rate for unresectable chondrosarcomas. ER -