3335 - Evaluation of the Efficacy and Safety of Particle Therapy for Kidney Cancer through a Multicenter Registry Study and Meta-Analysis
Presenter(s)
K. Nishioka1, H. Ishikawa2, S. Toyama3, O. Suzuki4, T. Okimoto5, T. Ogino6, M. Murakami7, H. Tamamura8, Y. Shibamoto9, K. Maruo10, K. Umehara2, T. Hashimoto1, H. Aoyama11, and H. Sakurai12; 1Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan, 2QST Hospital, National Institutes for Quantum Science and Technology, Chiba, Chiba, Japan, 3Ion Beam Therapy Center, SAGA HIMAT Foundation, Tosu, Saga, Japan, 4Osaka Heavy Ion Therapy Center, Osaka, Osaka, Japan, 5Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan, 6Medipolis Proton Therapy and Research Center, Ibusuki, Kagoshima, Japan, 7Southern TOHOKU Proton Therapy Center, Koriyama, Fukushima, Japan, 8Fukui Prefectural Hospital Proton Therapy Center, Fukui, Fukui, Japan, 9Narita Memorial Proton Center, Toyohashi, Aichi, Japan, 10Department of Biostatistics, University of Tsukuba, Tsukuba, Ibaraki, Japan, 11Department of Radiation Oncology, Faculty of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan, 12Department of Radiation Oncology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
Purpose/Objective(s):
This study aimed to evaluate the efficacy and safety of particle therapy for kidney cancer by analyzing a multicenter registry study in Japan and comparing outcomes with those of stereotactic body radiation therapy (SBRT) through a systematic review and meta-analysis.
Materials/Methods:
Patients with kidney cancer who received particle therapy as advanced medical care between May 1, 2016, and October 31, 2022, were identified from two Japanese national registries: Proton Net (proton therapy) and J-CROS (carbon-ion therapy). Outcomes assessed included overall survival (OS), progression-free survival (PFS), local control (LC), incidence of grade 3 or higher late adverse events, and change in estimated glomerular filtration rate (eGFR) at 3 years post-treatment. OS and PFS were estimated using the Kaplan-Meier method, while LC and incidence of late adverse events were analyzed using competing risk models. A systematic review was conducted following predefined search criteria, and a meta-analysis was performed using selected studies.
Results:
Fifty-nine patients (34 proton, 25 carbon-ion; median age 71 years) were analyzed, including 15 patients (25%) with tumors >40 mm in diameter. The median follow-up was 44.3 months. The 3-year OS and PFS rates were 92.0% and 82.7%, respectively. Four patients experienced local recurrence, resulting in a 3-year LC rate of 94.6%. One case of grade 3 cholecystitis was observed, though it was deemed unrelated to particle therapy; the 3-year incidence of grade 3 or higher late adverse events was 2.6%. The median change in eGFR at 3 years post-treatment was -12.0 mL/min/1.73m² (IQR: -20.1 to -1.3). The systematic review identified 14 eligible studies. In the meta-analysis, the 3-year OS rate was significantly higher in the particle therapy group compared to the SBRT group (94.9% vs. 79.2%, p = 0.0051), while no significant differences were found for PFS, LC, incidence of late adverse events, or changes in eGFR. Additionally, there were no significant differences in outcomes between proton and carbon-ion therapy.
Conclusion:
Particle therapy for kidney cancer demonstrates efficacy and safety at least comparable to SBRT, supporting its potential as a viable and safe treatment option. No significant differences were observed between proton and carbon-ion modalities. These findings support the clinical utility and broader adoption of particle therapy for kidney cancer.