Treatment Planning Comparison for Carbon Ion Radiotherapy, Proton Therapy and Intensity-modulated Radiotherapy for Spinal Sarcoma.

BACKGROUND/AIM: Carbon ion radiotherapy (CIRT), proton therapy (PT) and intensity-modulated radiotherapy (IMRT) are new radiation modalities suitable for treatment of spinal sarcomas. The objective of the study was to compare the treatment planning of these modalities. PATIENTS AND METHODS: We conducted a treatment planning comparison of the three modalities using a phantom imitating a spinal sarcoma and then six actual cases with spinal tumors. A uniform biological effective dose (BED) of 90 Gy10 was prescribed in previously reported fractionation schedules for each modality. The surface/center spinal cord dose constraints were set to BED of 96/77 Gy(E)3, respectively. RESULTS: CIRT achieved better homogeneity of dose distribution and coverage of target than PT independently of tumor extent around the spinal cord. In IMRT plans, the spinal cord dose was higher than that under CIRT and PT and coverage of the target deteriorated depending on the tumor extension. CONCLUSION: CIRT was most appropriate for the treatment of advanced spinal sarcomas.