Carbon ion therapy for stage I lung cancer is given once a day, and often in just one session. In a Japanese national registry study (J-CROS-LUNG, published in the Journal of Thoracic Oncology), 136 patients with operable stage I non-small cell lung cancer reached a 5-year overall survival of 81.8% and a 5-year local control of 95.8%. Carbon ion therapy for early-stage non-small cell lung cancer has been covered by Japan's public insurance since 2024; patients from abroad receive it as self-pay care. This article summarizes the latest results, the single-session schedule, eligibility and fees for overseas patients. To check whether it fits your case, use our early lung cancer eligibility and cost consultation.
Stage I lung cancer carbon ion therapy: what has been reported recently?
In stage I non-small cell lung cancer the tumor stays within the lung without spread to lymph nodes or other organs. Surgery is the standard treatment, but it is a heavy burden for patients in their late 70s or with weak heart or lung function, and some patients prefer not to have surgery. Carbon ion therapy has become a strong option for them.
Carbon ions stop at a set depth and release most of their energy there (the Bragg peak), so a high dose can be focused on a small lung tumor while sparing healthy lung. See What Is Carbon Ion Therapy? for the principles.
The Japan Carbon-ion Radiation Oncology Study Group (J-CROS) has registered and followed lung cancer patients treated at all Japanese facilities since 2016. A key result concerns stage I patients who could have had surgery but chose carbon ion therapy: 136 patients (median age 74) treated in 2016–2018 and followed for a median of 56 months. The French National Cancer Institute (INCa) research bulletin also featured this study.
How does single-session carbon ion therapy perform?
QST Hospital (Chiba) established a method of treating early lung cancer with a single session of 50 Gy (RBE). Its physicians followed 57 patients with T1–2N0M0 non-small cell lung cancer treated this way in 2011–2016 for a median of 61 months (Cancers, 2021). The median age was 75, and 22 patients were medically inoperable.
| Study | Patients | Regimen | Key results |
|---|---|---|---|
| J-CROS-LUNG, operable stage I (J Thorac Oncol) | 136, median age 74 | Society-approved regimens | 5-year OS 81.8%, cause-specific survival 91.2%, local control 95.8% |
| QST single-session long-term results (Cancers 2021) | 57, median age 75 | 50 Gy (RBE), 1 session | 5-year local control 91.8%, OS 81.7% |
| J-CROS-LUNG, stage I with interstitial lung disease (J Radiat Res 2023) | 30 | 50–69.6 Gy (RBE), 5 schedules | 3-year local control 88.1%, grade >2 pneumonitis in 1 (3.3%) |
A 5-year local control above 90% means that in more than nine out of ten patients the cancer did not grow back at the treated site. In the operable-patient study there was no grade 4 or higher toxicity and one case of grade 3 radiation pneumonitis. The QST single-session study reported no grade 2 pneumonitis.
Patients with interstitial lung disease have few options because conventional radiotherapy can worsen pneumonitis. In the registry study of 30 such patients, 3-year local control was 88.1%, and the authors concluded that carbon ion therapy can be a safe option. Lung function results are essential for this assessment. See side effects of carbon ion therapy.
How does it compare with SBRT?
Stereotactic body radiotherapy (SBRT) with X-rays is also widely used. Gunma University Heavy Ion Medical Center compared 89 patients with peripheral early lung cancer treated in 2010–2015 (62 carbon ion, 27 SBRT; Cancers, 2021).
| 3-year outcome | Carbon ion | SBRT |
|---|---|---|
| Overall survival | 80.1% | 71.6% |
| Local control | 87.7% | 79.1% |
| Grade 3 pneumonitis | 1 (1.6%) | 1 (3.7%) |
Survival and local control were higher with carbon ions, with no grade 4 or higher late toxicity in either group. As a single-center retrospective study, the authors recommended confirmation in a randomized trial. Compared with surgery, carbon ion therapy needs no incision and little hospital stay. The best choice depends on tumor location, size and lung function. See also carbon ion vs proton therapy.
Eligibility and schedule
According to QST Hospital, early lung cancer candidates have a primary lung tumor with no distant metastasis and no lymph node spread (N0). If the tumor is close to the bronchi or esophagus, treatment is split into several sessions over about 3 weeks. Locally advanced disease is treated in 16 sessions over about 4 weeks; see stage III lung cancer carbon ion therapy.
| Step | Details | Duration (per institution) |
|---|---|---|
| 1. Records review | Images and pathology sent via a coordinator | Varies |
| 2. First visit in Japan | Examination, extra imaging, consent | A few days to about 1 week |
| 3. Preparation | Immobilization device, planning CT with breathing motion | 1–2 weeks wait |
| 4. Irradiation | 1 session for peripheral tumors, split for central ones | 1 day or about 3 weeks |
| 5. Follow-up at home | Regular chest CT with your local hospital | Several years |
For a single session, plan about 3–4 weeks from first visit to return home. See carbon ion therapy treatment period.
Cost for overseas patients
Residents in Japan can use public insurance for early non-small cell lung cancer since 2024. Overseas patients without Japanese public insurance pay as self-pay patients. QST Hospital lists the following (viewed October 19, 2026; no reference date shown on the page).
| Item | Amount (QST Hospital) | Note |
|---|---|---|
| Carbon ion therapy fee | JPY 5,786,000 (tax incl.) | Self-pay |
| Consultations, tests, admission | JPY 33 per medical point (tax incl.) | Based on care received |
| Medical coordinator fee | Not included | Varies by coordinator |
Add extra tests, interpreting, lodging and travel. A single session means a shorter stay and lower living costs. Compare hospitals in carbon ion therapy cost in Japan.
Eligibility and schedule depend on lung function, tumor location and prior treatment. Send us your records and we will help prepare a consultation with a Japanese institution — Contact · +82-2-517-5117
Documents to prepare
- Pathology report: histology; if no biopsy was possible, a physician's note explaining why
- Imaging CD and reports: chest CT, PET-CT, brain MRI
- Pulmonary function tests, including any interstitial lung disease or emphysema
- Referral letter: why surgery is not chosen, and the course so far
- Medications and conditions: anticoagulants, heart disease, prior chest radiotherapy
Useful questions: is a single session possible for my tumor location, how long must I stay, and where will follow-up take place? Japanese centers are listed in Japanese Institutions.
FAQ
Is stage I lung cancer really treated in one day?
Peripheral early lung cancer is often treated at QST Hospital with a single 50 Gy (RBE) session. Tumors near critical organs are treated in several sessions over about 3 weeks.
What is the survival rate?
In the Japanese registry, 136 operable stage I patients had a 5-year overall survival of 81.8% and local control of 95.8%. The QST single-session study reported a 5-year survival of 81.7%.
Can I choose carbon ion therapy even if surgery is possible?
Yes. The registry study reports exactly such patients. The final decision is made by Japanese physicians after reviewing images and pathology.
Is it possible with interstitial lung disease?
In the registry, 30 stage I patients with interstitial lung disease were treated, with a 3-year local control of 88.1%. Please submit lung function test results.
How much does it cost?
For overseas patients, QST Hospital lists JPY 5,786,000 (tax incl., viewed October 19, 2026), with consultations and tests charged at JPY 33 per medical point.
Related articles
Wondering if carbon ion therapy is possible for you, and what it costs?
We help you prepare consultations with Japanese institutions and provide medical interpreting.
Free consultationCall +82-2-517-5117Sources
- J Thorac Oncol — Five-year survival after CIRT for operable stage I NSCLC (J-CROS-LUNG)
- INCa Nota Bene Cancer n°582 — summary of the J-CROS-LUNG operable stage I study
- Ono T, et al. Cancers 2021;13(1):112 — Long-term results of single-fraction CIRT for NSCLC
- Okano N, et al. J Radiat Res 2023;64(S1):i2-i7 — CIRT for stage I NSCLC with ILD (J-CROS-LUNG)
- Miyasaka Y, et al. Cancers 2021;13(2):176 — CIRT vs SBRT for early-stage NSCLC (Gunma)
- QST Hospital — Lung cancer (indications, English)
- QST Hospital — For patients from abroad (fees, procedure)
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.