Carbon ion therapy for osteosarcoma and other sarcomas has long been used for tumors of the pelvis, spine and sacrum that are difficult to remove surgically. In Japan, bone and soft tissue sarcoma was the first condition for which carbon ion therapy received public insurance coverage, and QST Hospital has treated 764 patients with these tumors. In a study of 95 patients with sacral chordoma, the 5-year local control rate was 88% and the 5-year survival rate was 86%. To find out whether your case may be eligible and what the cost and schedule would be, please send your records through our sarcoma carbon ion therapy consultation.
Who is eligible for carbon ion therapy for sarcoma?
Sarcomas are rare cancers arising in bone, muscle, fat, cartilage and other connective tissue. Many respond poorly to conventional X-ray radiation, so options can become limited when surgery is difficult. Carbon ions release their energy at a set depth (the Bragg peak) and have a strong cell-killing effect, which is why they have long been used for radioresistant sarcomas. See What Is Carbon Ion Therapy? for the basics.
The eligibility criteria published in QST Hospital's English guide are summarized below. Gunma University Heavy Ion Medical Center similarly requires a measurable tumor and no metal such as screws at the treatment site, with general conditions of a tumor up to 12 cm, no widespread metastasis and performance status 0–2.
| Item | QST Hospital criteria | Records checked |
|---|---|---|
| Surgery | Localized tumor where curative surgery is difficult due to the tumor or the patient's condition | Surgeon's opinion |
| Diagnosis | Sarcoma confirmed by pathology | Pathology report |
| Visible tumor | Gross tumor visible on MRI and CT | Recent MRI and CT |
| Metastasis | No systemic metastasis | PET-CT or chest CT |
| Metal | No metal implants in the treatment area | Operative notes (screws, prostheses) |
| Recurrence | Recurrence after surgery is eligible; recurrence after radiation needs consultation | Previous treatment records |
According to QST Hospital's materials for physicians, sacral chordoma is the most common condition treated. Osteosarcoma of the arms and legs is in principle not a target; candidates are mainly trunk tumors around the pelvis or spine where surgery is difficult or would cause major loss of function. Chondrosarcoma and soft tissue sarcoma are also treated. More background is in Applicable Cancers.
What are the results for chordoma, chondrosarcoma and osteosarcoma?
Sarcoma is one of the areas where Japan has built the most experience with carbon ion therapy. Key human results are summarized below.
| Study | Patients | Main results |
|---|---|---|
| QST Hospital (Japanese multicenter study J-CROS, 2015) | 764 patients, all histologies | 5-year local control 68%, 5-year survival 65% |
| Imai et al., British Journal of Radiology 2011 | 95 patients with unresectable sacral chordoma (median age 66) | 5-year local control 88%, 5-year survival 86%, 91% remained ambulatory |
| Mohamad et al., Oncotarget 2018 | 26 children and adolescents with inoperable trunk osteosarcoma (median age 16) | 5-year local control 62.9%; all but one patient could walk |
The chordoma authors concluded that carbon ion therapy appears effective and safe for sacral chordoma and is a promising alternative to surgery. Because major surgery in this area can affect walking, bowel and bladder function, controlling the tumor while preserving function matters greatly to patients. In the pediatric osteosarcoma study there were no treatment-related deaths, and the authors reported local control and survival they described as improved compared with conventional treatment. Results vary by histology and grade, so your expected benefit should be discussed with the treating physicians.
Side effects depend on how close the tumor is to skin, nerves and bowel. In the chordoma study, 2 patients had skin complications requiring grafts and 15 had sciatic nerve symptoms requiring ongoing medication. Hospitals minimize the treated area with immobilization devices and imaging, and manage patients with regular follow-up.
How long is the treatment and stay in Japan?
Most bone and soft tissue tumors are treated in 16 fractions over 4 weeks (QST Hospital physician materials; Gunma University overseas patient guide). The studies above also used 16 fractions. Each session is short, but plan your stay to include preparation time.
| Step | What happens | Approximate time |
|---|---|---|
| 1. Records review | Records sent via a coordinator; physicians decide eligibility | Before travel |
| 2. First visit and preparation | Examination, immobilization device, CT with the device, MRI or PET-CT if needed | A few days |
| 3. Treatment planning | Physicians design beam directions and area (QST usually allows 1–2 weeks) | About 1–2 weeks |
| 4. Irradiation | Once a day on weekdays, 16 sessions | About 4 weeks |
| 5. After returning home | Regular imaging follow-up with local and Japanese hospitals | Several years |
QST Hospital notes that patients may return home during planning if they come back by the day before treatment begins. Patients with pain or nerve symptoms may find travel and device fitting tiring, so arrange lodging and a companion in advance. See the Japanese Institutions page to compare centers.
How much does sarcoma carbon ion therapy cost?
Overseas patients do not use Japanese public insurance and pay the hospital's self-pay fee. The carbon ion fee is a fixed amount per course, regardless of the number of sessions.
| Hospital | Carbon ion fee for overseas patients | Additional costs |
|---|---|---|
| QST Hospital (Chiba) | JPY 5.786 million (tax included) | Hospital stay, visits and tests at JPY 33 per medical fee point; coordinator fee |
| Osaka Heavy Ion Therapy Center | JPY 4.8 million + consumption tax | Visits, tests, drugs; travel, lodging and medical tourism service fees |
Amounts are from each hospital's official page (accessed October 20, 2026) and may change with exchange rates or revisions.
To learn which hospital to contact first with your records and the expected total cost, please use our consultation form (phone +82-2-517-5117).
Document checklist before consultation
Japanese carbon ion centers first review an overseas patient's records to decide eligibility. QST Hospital sends the required list by email, and Gunma University asks coordinators to collect and forward records. For sarcoma, the following helps speed up the review.
- Referral letter: diagnosis, stage and treatment history (English translation)
- Pathology report: histology (chordoma, chondrosarcoma, osteosarcoma, etc.) and grade
- Imaging CD (DICOM): MRI and CT from the last 1–2 months, PET-CT or chest CT for metastasis
- Operative notes: extent of surgery for recurrence and any metal (screws, plates, prostheses) at the site
- Previous radiation or chemotherapy: site, dose and dates
- Current condition: pain, walking ability, bowel and bladder symptoms, medications
Complete records shorten the time to a physician's decision and allow more accurate schedule and cost estimates.
Frequently asked questions
Can osteosarcoma of the arm or leg be treated with carbon ions?
Limb osteosarcoma is usually treated surgically, and QST Hospital states it is in principle not a target. Trunk tumors in the pelvis, spine or sacrum that are difficult to remove are the main candidates.
How does carbon ion therapy for chordoma compare with surgery?
In a study of 95 sacral chordoma patients, 5-year local control was 88%, 5-year survival 86%, and 91% remained ambulatory. The authors called it a promising alternative to surgery. The comparison for your case is made with your physicians.
Is metal in the body a problem?
Metal in the treatment area makes dose calculation difficult, so both QST and Gunma exclude such cases. Metal far from the site may not matter, so please send operative notes.
Do I need to be hospitalized during treatment?
Most patients are treated as outpatients and each session is short. Admission may be recommended depending on pain or mobility, and is charged separately.
Related articles
Wondering if carbon ion therapy is possible for you, and what it costs?
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Free consultationCall +82-2-517-5117Sources
- QST Hospital — Bone and soft tissue tumors (indications for carbon ion radiotherapy)
- QST Hospital — Carbon ion radiotherapy for patients from abroad (fees and application)
- QST Hospital physician materials: carbon ion therapy for bone and soft tissue tumors (Japanese)
- Imai R, et al. Carbon ion radiotherapy for sacral chordoma. Br J Radiol 2011;84:S48-54
- Mohamad O, et al. Carbon ion radiotherapy for inoperable pediatric osteosarcoma. Oncotarget 2018;9:22976-22985
- Gunma University Heavy Ion Medical Center — Information for overseas patients
- Osaka Heavy Ion Therapy Center — Treatment fees (Japanese)
General information based on public sources; not a substitute for diagnosis or treatment. Eligibility is decided by the treating physicians. Written by the FTH editorial team.