Carbon ion therapy eligibility is first screened with three questions: is the cancer confined to one area, has it been confirmed by biopsy, and can the patient's general condition tolerate treatment? QST Hospital (Chiba, Japan) publishes eligibility criteria for carbon ion therapy in 15 disease groups, including prostate, lung, liver, pancreatic, head and neck, bone and soft tissue sarcoma, cervical cancer and recurrent rectal cancer, and many of these are now covered by Japan's public insurance. This article puts QST Hospital's published criteria into a table by cancer type and explains the situations where treatment is difficult and the options that remain. To check eligibility with your own records, send your files for an eligibility consultation.
How is eligibility for carbon ion therapy decided?
Carbon ion therapy (heavy ion therapy) is a local treatment that targets tumors with carbon ions, which release their energy at a set depth in the body. The principle is explained in What Is Carbon Ion Therapy? Because it is a local treatment, the criteria center on whether the cancer is gathered inside the area to be irradiated.
Across QST Hospital's disease pages, the common conditions are:
- Confirmed diagnosis: cancer must be confirmed by pathology (biopsy). Patients without a definitive diagnosis are not eligible.
- Localized disease: no distant metastasis, or only a few metastases (for example three or fewer) with other lesions controlled.
- Distance from nearby organs: if the tumor touches or invades the stomach or bowel, other treatments may be recommended first.
- General condition: the patient must be well enough for treatment; serious complications make it difficult.
- Relation to surgery: for many cancers, eligibility applies when surgery is difficult or not desired. Prostate cancer is the exception: almost all patients without metastasis qualify.
The final decision is made by the hospital's cancer board after reviewing images and pathology. Results can differ for the same stage, and some patients who seem outside the general criteria turn out to be eligible after review.
Eligibility criteria by cancer type
The table follows QST Hospital's English indication pages. Schedules are listed only where the page states them.
| Cancer | Eligible when | Schedule | Conditions to note |
|---|---|---|---|
| Prostate cancer | Localized or locally advanced, no metastasis (T1c–T4N0M0), pathologically confirmed | Shortened from 5 weeks to 3 weeks | Recurrence after prostatectomy or after hormone therapy excluded |
| Early lung cancer | Primary lung cancer without nodal spread (Tis, T1–T4N0, excluding T4 by organ invasion) | Usually 1 day; about 3 weeks if a key organ is near | No distant metastasis |
| Locally advanced lung cancer | Non-small cell lung cancer with nodal spread (N1–N3) or organ invasion | 16 fractions, 4 weeks | No pleural or pericardial effusion |
| Hepatocellular carcinoma | Difficult to treat with conventional curative methods, no disease outside the liver, about 3 or fewer lesions | Per hospital | Near the GI tract, surgery or RFA may be preferable |
| Intrahepatic bile duct cancer | Unresectable or recurrent, mass-forming type | Per hospital | No disease outside the liver |
| Pancreatic cancer | Preoperative for stage 0–3; stage 1–3 when curative treatment is difficult; local recurrence after surgery | Preoperative 8 fractions (2 weeks); curative 12 fractions (3 weeks) | GI invasion; metal biliary stent (plastic stent acceptable) |
| Head and neck cancer | Non-squamous cancers (e.g. adenoid cystic), mucosal melanoma, head and neck sarcoma | Per hospital | Squamous cell cancer of oral cavity, pharynx, larynx excluded |
| Bone and soft tissue sarcoma | Localized tumor where curative surgery is difficult, visible on MRI and CT | Per hospital | Metal implants in the field; systemic metastasis |
| Cervical cancer | Stage II–IVA adenocarcinoma (any size), squamous cell carcinoma 6 cm or larger | Per hospital | Prior surgery or radiation excludes |
| Recurrent rectal cancer | Pelvic recurrence or abdominal lymph node recurrence after surgery | Per hospital | Primary colorectal cancer not treated; margin from bladder and bowel needed |
| Lung metastases | Primary treated, no disease outside the lungs, 3 or fewer | Per hospital | 4 or more: other treatment considered |
These criteria are a starting point. Stage IV pancreatic cancer with only para-aortic lymph node metastasis may qualify, and adenoid cystic carcinoma with lung metastases may be considered if long-term survival is expected. See prostate cancer carbon ion therapy, pancreatic cancer carbon ion therapy, liver cancer criteria and head and neck cancer carbon ion therapy.
When is carbon ion therapy difficult?
- Widespread metastasis: when the liver, lungs, peritoneum or distant nodes are widely involved, systemic treatment such as chemotherapy or immunotherapy becomes central.
- Tumors touching or invading the GI tract: the stomach and bowel are sensitive to high doses. Cancers of the GI tract itself, such as stomach or duodenal cancer, are not on the list.
- Certain histologies: squamous cell cancer of the oral cavity, pharynx and larynx, and cervical squamous cell cancer under 6 cm, where standard treatment is used.
- Prior treatment: cervical cancer after surgery or radiation and prostate cancer recurring after prostatectomy are excluded, while recurrent rectal cancer and recurrent sarcoma can be discussed even after radiation.
- Metal in the field: metal implants near a sarcoma or a metal biliary stent in pancreatic cancer complicate planning.
For recurrence in a previously irradiated area, good results with carbon ion re-irradiation have been reported for some cancers; see carbon ion therapy after radiotherapy. If carbon ions are not suitable, proton therapy or other radiotherapy may be an option; see carbon ion vs proton therapy.
Can cancers outside the criteria be considered?
QST Hospital states that cancers not on the insurance or clinical trial lists may be considered when all three conditions apply:
- Other treatments cannot be used or are unlikely to work well.
- The local treatment effect would be a major benefit to the patient.
- Based on theory or experience, it could work better than other treatments.
Examples include early cancer (T1–T2N0M0) in patients who cannot have or decline surgery, locally advanced cancers at various sites, and localized metastatic or recurrent cancer. The range keeps widening. A Japanese national registry study (International Journal of Particle Therapy, 2024) reported 13,224 patients treated at five Japanese facilities from 2019 to 2022, and monthly patient numbers for hepatocellular carcinoma and locally advanced pancreatic cancer rose 1.8 to 1.9 times after insurance coverage began in 2022. The Japanese Society for Radiation Oncology (JASTRO) reported that 11 carbon ion indications moved from Advanced Medical Care to insurance coverage in June 2024.
Overseas patients are not covered by Japanese public insurance and are treated as self-pay. Published prices are in carbon ion therapy cost, and facilities are listed in Japanese Institutions.
Records needed for an eligibility review
- Referral letter from your doctor: diagnosis, stage and treatment history
- Pathology report: biopsy result and histology (adenocarcinoma, squamous cell, etc.)
- Recent imaging: CT, MRI and PET-CT original images (DICOM) on CD, with reports
- Treatment history: surgery records, drug names and periods, and site and dose of any radiotherapy
- Recent blood tests and tumor marker values
- Information on metal implants, stents or devices such as pacemakers
FTH translates and organizes these records in the format Japanese hospitals request and supports consultations and medical interpreting. For stay planning, see carbon ion therapy treatment period.
Frequently asked questions
Can stage IV cancer be eligible for carbon ion therapy?
Widespread metastasis makes it difficult, but oligometastatic disease can qualify. QST Hospital uses three or fewer lung or liver metastases as a guide, and considers stage IV pancreatic cancer with only para-aortic lymph node metastasis.
Can I receive carbon ion therapy after previous radiotherapy?
It depends on the cancer. Cervical cancer after radiation is excluded, but pelvic recurrence of rectal cancer and recurrent sarcoma can be discussed. Records of the previous site and dose are important.
Is there an age limit?
QST Hospital's criteria do not state an upper age limit. General condition and complications matter more than age, and older patients for whom surgery is a burden can consider carbon ion therapy instead.
Can I learn whether I am eligible before travelling to Japan?
Yes. You can first receive a written review (second opinion) based on images and pathology, then get the final decision at the first visit in Japan. Start with a consultation request or call +82-2-517-5117.
Related articles
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- QST Hospital — Indications for Carbon Ion Radiotherapy (index)
- QST Hospital — Prostate Cancer
- QST Hospital — Lung Cancer
- QST Hospital — Liver Cancer
- QST Hospital — Pancreatic Cancer
- QST Hospital — Head and Neck Cancer
- QST Hospital — Bone and Soft Tissue Tumor
- QST Hospital — Colorectal Cancer
- QST Hospital — Gynecological Cancer
- QST Hospital — Other Diseases
- QST — Carbon Ion Radiotherapy overview (2024.6)
- Kubo N, et al. Int J Part Ther 2024;14:100634 — Japanese National Registry Study
- JASTRO response to the Advanced Medical Care Committee, Sep 2024 (Japanese document)
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.