Carbon Ion Therapy for Kidney Cancer: Results, 3-Week Schedule, Cost

Carbon ion therapy for kidney cancer is an option that Japanese carbon ion cancer treatment centers have offered to people with renal cell carcinoma who cannot easily have surgery, or who would need dialysis right after surgery. At QST Hospital (Chiba, Japan), 19 patients treated in 1997–2014 had a 5-year local control rate of 94.1% and a 5-year cancer-specific survival rate of 100%, and a prospective 12-fraction, 3-week trial of 8 patients reported 100% local control. QST Hospital currently treats kidney cancer within clinical studies or when it judges the therapy to be indicated, and a 4-fraction, 1-week study is ongoing. This article summarizes the results, who may be eligible, the schedule and the published fee for overseas patients. To check eligibility with your CT/MRI and kidney function results first, send them via kidney cancer carbon ion therapy eligibility and cost consultation.

Why consider carbon ion therapy for kidney cancer?

Most cancers arising in the kidney are renal cell carcinoma. For localized disease, surgery that removes part or all of the kidney is the standard treatment. In practice, however, many patients are poor candidates for surgery: older patients for whom general anesthesia is risky because of heart or lung disease or stroke risk, patients whose other kidney is atrophic or who have a single kidney and would need dialysis immediately after surgery, and patients who cannot receive blood transfusion for religious reasons. Tumors larger than 4 cm are often outside the range of local ablation such as cryoablation or radiofrequency ablation.

Renal cell carcinoma is known to respond poorly to conventional X-ray radiotherapy. Carbon ion beams release their energy at a set depth and then stop (the Bragg peak), and they damage cells more strongly than X-rays. This allows a high dose to be concentrated on radioresistant renal cell carcinoma while sparing more of the surrounding healthy kidney and bowel. See What Is Carbon Ion Therapy? for an illustrated explanation. In a 2022 review in the International Journal of Urology, QST physicians cited two studies showing the efficacy of carbon ion therapy for renal cell carcinoma.

Results: 19 patients followed long term and a 12-fraction trial

Outcome data for carbon ion radiotherapy in kidney cancer come mainly from two QST Hospital studies: long-term follow-up of 19 patients with primary renal cell carcinoma treated in 1997–2014, and a prospective trial of a 12-fraction, 3-week schedule started in 2013.

The 5-year disease-free survival in the long-term study was 68.9%. In the 12-fraction trial, the investigators set 72 Gy (RBE) as the recommended dose. The way the tumors responded is worth knowing: rather than shrinking markedly, renal cell carcinomas responded with necrotic areas inside the tumor gradually enlarging over time. If a follow-up CT does not show much change in size, remember that physicians judge response by contrast enhancement and the extent of necrosis together.

Both studies are single-center with small numbers of patients. Still, long-lasting tumor control in patients for whom surgery was difficult is meaningful information for patients and families with few other options. In a 2023 review, physicians at Italy's National Center for Oncological Hadrontherapy (CNAO) also described carbon ion therapy as an effective treatment for rare, radioresistant and difficult-to-treat tumors.

What about kidney function, dialysis and side effects?

The question patients and families ask most often is whether kidney function will decline to the point of dialysis. The results differ by kidney status before treatment.

• Patients without definitive renal comorbidities: in the long-term study, 14 of 19 patients did not progress to grade 3 or higher chronic kidney disease. In the 12-fraction trial, eGFR in the 6 evaluable patients fell by an average of 10.8 mL/min/1.73m², and no patient progressed to grade 3 or higher chronic kidney disease.
• Patients with diabetic nephropathy, an atrophic kidney or a single kidney: 4 of 5 progressed to grade 4 chronic kidney disease. Because these patients might have needed dialysis immediately after surgery, it is important to agree goals with the medical team in advance, including delaying the start of dialysis.
• Non-renal side effects: mostly mild grade 1 skin reactions, managed with moisturizing and reducing friction.

The investigators concluded that carbon ion therapy "is a safe treatment for primary RCC patients without definitive renal comorbidities," and QST Hospital's patient information also explains that there was no severe renal impairment except in patients with prior diabetic nephropathy or a single kidney. Side effects and their management for other cancers are covered in Carbon Ion Therapy Side Effects.

Who is eligible for carbon ion cancer treatment?

QST Hospital's English information states that it treats renal cell carcinoma diagnosed by biopsy or imaging, mainly in patients for whom standard treatment is difficult because of complications, or who would need dialysis immediately after surgery. Combined with the criteria used in the 12-fraction trial:

Distance from the bowel, function of the other kidney and prior targeted therapy are judged from images and test results. See also Kidney Cancer Carbon Ion Therapy Criteria. Preparing the following speeds up the review:

• The most recent abdominal contrast CT or MRI (original image files on CD/DVD)
• Biopsy report (if performed), medical certificate and referral letter
• Kidney function tests such as serum creatinine and eGFR, and renal scan results (if any)
• List of conditions such as diabetes or heart disease, current medications and previous treatment records

Schedule and cost

QST Hospital began carbon ion radiotherapy for kidney cancer in 1997 with 16 fractions over 4 weeks and shortened it to 12 fractions over 3 weeks from 2013. A prospective study of 4 fractions over 1 week has been under way since 2017, and patients judged eligible outside the study criteria are treated in 12 fractions. Treatment is usually given once a day, 4 days a week, and the irradiation itself is painless.

The cost reference is the amount published in QST Hospital's information for overseas patients (checked October 23, 2026): the self-pay fee for carbon ion therapy is 5,786,000 yen (tax included), and hospitalization, outpatient visits and tests are charged separately at 33 yen per medical fee point (tax included). Coordinator fees, flights, accommodation and interpreting are not included. Kidney cancer is not on the list of conditions covered by Japan's public health insurance in QST Hospital's leaflet for physicians (2022 edition), so overseas patients should expect self-pay treatment. See Carbon Ion Therapy Cost in Japan for hospital-by-hospital fees, Carbon Ion Therapy Treatment Period for the length of stay, and Japanese Institutions for centers offering carbon ion therapy in Japan.

Kidney function results and images make the review much faster. Send your records for a consultation or call +82-2-517-5117.

FAQ

Can I have carbon ion therapy instead of kidney cancer surgery?

Surgery is standard for patients who can have it. Carbon ion therapy is mainly considered when complications make surgery difficult or when surgery would require dialysis immediately afterwards. The final decision is made by physicians at the Japanese carbon ion cancer treatment center based on images and test results.

How many sessions are needed?

At QST Hospital the standard is 12 fractions over about 3 weeks; eligible patients may receive 4 fractions over 1 week within a study. Treatment is usually once a day, 4 days a week.

Will I need dialysis after treatment?

In patients without definitive renal comorbidities, progression to grade 3 or higher chronic kidney disease was not reported in the studies. When kidney function is already weak, such as with diabetic nephropathy or a single kidney, progression is possible, so kidney function goals are agreed with the team before treatment.

How much does carbon ion therapy for kidney cancer cost?

QST Hospital's self-pay fee for overseas patients is 5,786,000 yen (tax included, checked October 23, 2026); hospitalization, tests and living costs are extra. The total depends on the length of stay and the number of tests, so confirm an estimated total during consultation.

Is it possible with metastatic kidney cancer?

Trial criteria focused on localized renal cell carcinoma, but patients with metastasis could be considered when the expected prognosis was favorable. Send details of the metastatic sites and drug treatment history so eligibility can be checked first.

Sources

• Kasuya G et al. Updated long-term outcomes after carbon-ion radiotherapy for primary renal cell carcinoma. Cancer Science 2018;109(9):2873-2880
• Kasuya G et al. Prospective clinical trial of 12-fraction carbon-ion radiotherapy for primary renal cell carcinoma. Oncotarget 2019;10:76-81
• QST Hospital — Indications: Kidney cancer
• QST Hospital — For patients from abroad (fees)
• QST Hospital — Leaflet for physicians, insurance-covered conditions (2022, Japanese)
• Carbon-ion radiotherapy for urological cancers. International Journal of Urology 2022;29(10):1109-1119
• Orlandi E et al. The Role of Carbon Ion Therapy in the Changing Oncology Landscape (CNAO). Cancers 2023;15(20):5068

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.