Carbon ion therapy for prostate cancer has been covered by Japan's public health insurance since April 2018, making it an established form of carbon ion cancer treatment rather than an experimental one. Most non-metastatic prostate cancers, from low to high risk, are candidates, and treatment usually takes 12 sessions over about 3 weeks. Overseas patients, however, are treated as self-pay patients: QST Hospital lists 5.786 million yen (tax included) for international patients. This guide covers eligibility, preparation by risk group, the length of stay in Japan, cost components and the documents to prepare. To find out whether your biopsy and PSA results qualify, ask us about eligibility and cost for prostate cancer carbon ion therapy.
Who is eligible for carbon ion therapy for prostate cancer?
Carbon ion therapy (heavy ion therapy) accelerates carbon ions and stops them at the depth of the tumor, where they release most of their energy. The prostate sits right next to the rectum, bladder and urethra, so sparing these organs matters; carbon ions allow far fewer sessions in this location, which is why prostate cancer became one of the most common indications in Japan. The principle is explained in What Is Carbon Ion Therapy?
According to QST Hospital (National Institutes for Quantum Science and Technology, Chiba), candidates have primary prostate cancer confirmed by biopsy, stage T1c–T4 (including bladder neck involvement), with no lymph node (N0) or distant (M0) metastasis. The hospital states that basically all patients with non-metastatic prostate cancer are candidates. The following fall outside the criteria:
| Item | Eligible | Not eligible / reviewed separately |
|---|---|---|
| Diagnosis | Cancer confirmed by biopsy | Suspected on MRI or PET only |
| Stage | T1c–T4, N0, M0 | Spread to lymph nodes, bone or other organs |
| Prior treatment | Previously untreated prostate cancer | Recurrence after radical prostatectomy or after hormone therapy |
| General condition | Able to complete 3 weeks of outpatient or inpatient treatment | Serious comorbidities judged by physicians to make treatment difficult |
Gunma University Heavy Ion Medical Center similarly assesses clinical stage, the Gleason score from pathology, and the PSA value before biopsy. In practice, a consultation starts with the biopsy report and PSA history. See also our page on prostate cancer carbon ion therapy — eligibility and hormone therapy.
Outcomes — what do Japanese multicenter data show?
Prostate cancer is the disease with the largest experience in carbon ion therapy. Most figures below come from prospective or retrospective observational studies; no randomized trial comparing carbon ions with surgery or other radiotherapy has been published yet (a 2025 review by MedAustron researchers in Austria makes the same point). They should not be read as proof of superiority.
| Data | Patients | 5-year biochemical relapse-free rate (PSA) | Side effects |
|---|---|---|---|
| Japanese multicenter study (J-CROS 1501PR), 2016 | 2,157 (QST, Gunma, SAGA HIMAT) | Low 92%, intermediate 89%, high risk 92% | Grade 2 late urinary 4.6%, bowel 0.4%; grade 3+ 0% |
| SAGA HIMAT single center (ASTRO 2025) | 7,054 (2013–2024, 12 sessions) | Overall 92.0% (low 92.0%, intermediate 94.0%, high 90.4%) | 18 grade 3 events (6 rectal bleeding, 8 hematuria, etc.); no grade 4+ |
| QST Hospital cumulative data | 3,077 (1995–2018) | High risk 90.5% | Rectal bleeding of 2+ episodes ≤1% (recent results) |
Two points to keep in mind: most intermediate- and high-risk patients also received hormone therapy (androgen deprivation), so the results reflect the combination; and rectal or urinary bleeding can appear from about one year after treatment, so long-term follow-up is needed.
How long is treatment and the stay in Japan?
Irradiation itself takes 3 weeks (12 sessions), but the stay is longer: the first visit, tests, an immobilization device and a planning CT come first, and depending on risk group, hormone therapy may be needed for months beforehand. QST Hospital explains that preparation starts once eligibility is confirmed, followed by about 1–2 free weeks before treatment begins (patients who go home must return by the day before treatment starts).
| Step | What happens | Time (per institutions) |
|---|---|---|
| 1. Records review | Medical records submitted via coordinator → preliminary opinion | Gunma: coordinators reply within 5 days |
| 2. Hormone therapy | For intermediate/high risk, before carbon ions (ask whether it can start at home) | QST material: 2–6 months before |
| 3. First visit in Japan | Examination, extra tests, consent | A few days to about a week |
| 4. Preparation | Immobilization device, planning CT, treatment plan | Then 1–2 weeks of waiting |
| 5. Carbon ion irradiation | 4 days a week, a few minutes of beam each time | 12 sessions, about 3 weeks |
| 6. Follow-up at home | PSA tests, regular checkups with your local hospital | Several years |
In practice, patients either plan one stay of roughly 4–6 weeks from first visit to completion, or split the first visit and treatment into two trips. Treat the table as a planning guide only; schedules vary by institution and patient. Compare intake procedures in 7 carbon ion therapy hospitals in Japan.
Carbon ion therapy cost for overseas patients
Japanese residents are covered by insurance for prostate cancer, but patients without Japanese public insurance pay as self-pay patients. Listed fees and what they include differ by institution.
| Institution | Listed fee for international patients | Not included |
|---|---|---|
| QST Hospital (Chiba) | 5.786 million yen (tax included) | Hospital stay, visits and tests at 33 yen per fee point; coordinator fees |
| Osaka Heavy Ion Therapy Center | 4.8 million yen + consumption tax | Travel, lodging, medical tourism service fees |
| Gunma University Heavy Ion Medical Center | Fixed fee regardless of number of sessions (ask the center) | Travel, lodging, coordinator and consultation fees |
Basis: each institution's international patient pages, accessed 18 October 2026. None of the pages states an effective date, so confirm current fees at the time of consultation. On top of the treatment fee come hormone drugs, tests, medical interpreting, and 1–2 months of lodging and transport. See carbon ion therapy cost in Japan for more.
Cost and schedule depend heavily on risk group and hormone therapy. Send us your records and we will help prepare a consultation with a Japanese institution — contact us · +82-2-517-5117
Document checklist before a consultation
QST Hospital and Kanagawa i-ROCK both ask overseas patients to apply through a registered medical coordinator (or travel agency). The first medical opinion is based only on the records you send, so complete records speed up the reply.
- Biopsy pathology report with Gleason score and number of positive cores
- PSA history: value before biopsy and later changes, with dates
- Imaging on CD: prostate MRI, abdominal/pelvic CT, bone scan or PSMA PET, with reports
- Referral letter: treatment so far; if hormone therapy has started, drug names and start date
- Medical history and medications: anticoagulants, diabetes, inflammatory bowel disease, prior pelvic surgery or radiotherapy
- English translations of the referral letter and pathology report
Patients on anticoagulants are somewhat more prone to bleeding after treatment, so be sure to report them. Institutions are listed under Japanese institutions.
Frequently asked questions
Up to what stage can prostate cancer be treated with carbon ions?
T1c to T4, as long as there is no spread to lymph nodes or other organs. Metastatic (stage 4) disease is outside these criteria.
Can I have carbon ion therapy for recurrence after surgery?
QST Hospital excludes recurrence after radical prostatectomy and after hormone therapy. Discuss other options with your physicians.
Is hormone therapy always required?
Low-risk patients are usually treated with carbon ions alone. For intermediate and high risk, institutions recommend hormone therapy according to their protocols, with duration depending on risk.
Is treatment painful, and do I need to stay in hospital?
The beam causes no pain or heat; each session takes about 20 minutes including positioning. Both inpatient and outpatient treatment are possible. Frequent urination is common during treatment and usually resolves within 1–2 months.
Is the cost the same as for Japanese patients?
No. Japanese residents are insured, while overseas patients pay the self-pay fee set by each institution (e.g. QST 5.786 million yen tax included; Osaka 4.8 million yen + tax).
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 — Prostate cancer (indications, English)
- QST Hospital — For patients from abroad (fees, procedure)
- Nomiya T, et al. Radiother Oncol 2016;121:288-293 (J-CROS 1501PR)
- Fukunishi K, et al. ASTRO 2025 — SAGA HIMAT 7,054 patients
- Moll M, et al. Curr Opin Urol 2025;35:568-573 (MedAustron review)
- Gunma University Heavy Ion Medical Center — For international patients
- Kanagawa i-ROCK — Overseas patients
- Osaka Heavy Ion Therapy Center — Fees (Japanese)
- QST Hospital — Prostate cancer, for physicians (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.