Abstract
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.
Footnotes
Authors' Contributions
Shinnosuke Matsumoto: Investigation, writing - original draft. Sung Hyun Lee and Mai Fukahori: Investigation. Reiko Imai: Resources, Writing – review & editing, conceptualization. Taku Inaniwa, Naruhiro Matsufuji, and Ryosuke Kohno: Software. Shunsuke Yonai and Noriyuki Okonogi: Project administration, writing – review & editing. Shigeru Yamada and Nobuyuki Kanematsu: Supervision.
Conflicts of Interest
Dr. Kanematsu reports personal fees from Mitsubishi Electric Corporation, personal fees from Elekta, Inc., personal fees from Osaka International Cancer Treatment Foundation, outside the submitted work; In addition, Dr. Kanematsu has a patent JP6383429 issued, a patent JP5954705 with royalties paid to Mitsubishi Electric Corporation, Elekta, Inc, and RaySearch Laboratories, a patent JP5521225 with royalties paid to Mitsubishi Electric Corporation, Elekta, Inc, and RaySearch Laboratories, a patent JP4456045 with royalties paid to Mitsubishi Electric Corporation, a patent JP3531453 issued, and a patent JP Application 2018-177593 pending. Dr. Inaniwa reports grants from the Japan Society for Promotion of Science (JSPS), during the conduct of the study; personal fees from TOSHIBA Corporation, personal fees from Mitsubishi Electric Corporation, personal fees from Elekta, Inc., personal fees from Osaka Heavy Ion Therapy Center, outside the submitted work.
- Received September 28, 2020.
- Revision received October 5, 2020.
- Accepted October 6, 2020.
- Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved