The purpose of this study is to evaluate the safety and feasibility of primary hypofractionated irradiation of sacrococcygeal chordoma with carbon ions or protons using the raster scan technique.

The primary objective of this trial is safety and feasibility of hypofractionated irradiation in patients with sacrococcygeal chordoma using protons or carbon ions in raster scan technique for primary or additive treatment after R2 resection. The evaluation is therefore based on the proportion of treatments without Grade 3-5 toxicity (CTCAE, version 4.0) up to 12 months after treatment and/or discontinuation of the treatment for any reason as primary endpoint. Local-progression free survival, overall survival and quality of life will be analyzed as secondary end points.

Inclusion Criteria:

• Histological confirmation of sacrococcygeal chordoma
• Karnofsky performance status ≥ 70%
• Patients age 18 - 80 years
• Macroscopic tumour (MRI)
• Written informed consent

Exclusion Criteria:

• Lack of macroscopic tumour
• Tumor extension in craniocaudal direction >16cm
• Metal implants at the level of the tumor which could influence the treatment planning
• Inability of the patient to lie quiet for at least 20 minutes (eg due to pain)
• Prior radiotherapy of the pelvic region
• Simultaneous participation in another trial that could influence the results of the study
• Active medical implants without treatment approval at the time of ion irradiation (eg, cardiac pacemaker, defibrillator)