3517 - Clinical Outcomes of Particle Beam Therapy for T3N0M0 Non-Small Cell Lung Cancer: A Japanese National Prospective Registry Study
Presenter(s)
N. Kubo1, M. Nakamura2, K. Maruo3, M. Murakami4, H. Iwata5, S. Tokumaru6, T. Waki7, K. Shimizu8, M. Satouchi9, T. Hashimoto10, H. Ishikawa11, H. Suefuji12, H. Harada13, and Y. Shioyama14; 1Department of Radiation Oncology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan, 2National Cancer Center Hospital East, Kashiwa, Chiba, Japan, 3Department of Biostatistics, University of Tsukuba, Tsukuba, Ibaraki, Japan, 4Southern TOHOKU Proton Therapy Center, Koriyama, Fukushima, Japan, 5Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City University West Medical Center, Nagoya, Aichi, Japan, 6Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan, 7Department of Radiology, Tsuyama Chuo Hospital, Tsuyama, Okayama, Japan, 8Division of General Thoracic Surgery, Department of Surgery, Shinshu University School of Medicine, Matsumoto, Nagano, Japan, 9Hyogo Cancer Center, Akashi, Hyogo, Japan, 10Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan, 11QST Hospital, National Institutes for Quantum Science and Technology, Chiba, Chiba, Japan, 12Ion Beam Therapy Center, SAGA HIMAT Foundation, Tosu, Saga, Japan, 13Radiation and Proton Therapy Center, Shizuoka Cancer Center, Nagaizumi, Shizuoka, Japan, 14Ion Beam Therapy Center, SAGA-HIMAT Foundation, Tosu, Saga, Japan
Purpose/Objective(s): Definitive treatment options for patients with T3N0M0 non-small cell lung cancer (NSCLC) remain limited, particularly in elderly or medically inoperable cases. Particle beam therapy, including proton beam therapy (PBT) and carbon-ion radiotherapy (CIRT), offers highly conformal dose delivery and may improve tumor control with acceptable toxicity. This study evaluated clinical outcomes of particle therapy for T3N0M0 NSCLC using data from a Japanese national prospective multicenter registry.
Materials/Methods:
This multicenter prospective observational registry study was conducted across particle therapy centers in Japan. Patients with clinically staged T3N0M0 NSCLC treated with definitive particle beam therapy were included. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method, whereas the local failure rate was evaluated using the cumulative incidence function considering death as a competing risk. Treatment-related toxicity was assessed according to standard criteria. Multivariable analysis was performed using multiple imputation and stepwise variable selection.Results: A total of 96 patients were enrolled, including 70 treated with PBT and 26 treated with CIRT. The median age was 76.5 years (range, 49–90), and 81 patients were male. Interstitial pneumonia was present in 17 patients. The median vital capacity was 2680 mL. Eighteen patients were considered operable with lobectomy feasible. Systemic therapy was combined in 6 patients. With a median follow-up of 23.1 months (37.0 months among survivors), the 3-year OS and PFS rates were 48.1% (95% CI, 38.4–60.3) and 33.0% (95% CI, 24.3–44.8), respectively. The 3-year local failure rate was 19.2% (95% CI, 10.8–29.6). Grade =3 treatment-related toxicity occurred in 6 patients. In multivariable analysis, interstitial pneumonia was independently associated with worse OS (HR 3.44, p=0.001), whereas higher vital capacity was associated with improved OS (HR 0.37, p=0.002).
Conclusion: In this Japanese national prospective registry study, definitive particle beam therapy achieved favorable local control and encouraging survival outcomes for patients with T3N0M0 NSCLC, with acceptable severe toxicity. Given the elderly population and limited operability, particle therapy represents a definitive treatment option.