Fig. 1

Superior tumor control achieved by proton IRT over photon IRT. A Depiction of treatment scheme combining NBTXR3, XRT, PRT, and αPD1 in a murine model of αPD1-resistant lung cancer. B Mean growth trajectories of irradiated tumors (n = 7–10). C Mean growth trajectories of unirradiated tumors (n = 8–10). D Survival rates and median survival duration. E Count of lung metastases (N = 5). Female 129 Sv/Ev mice aged 8–12 weeks were subcutaneously injected with 344SQR αPD1-resistant lung cancer cells on the right leg (day 0) and the left leg (day 4) to establish primary and secondary tumors, respectively. NBTXR3 radio-enhancing nanoparticles were administered intratumorally into the primary tumors on day 7, followed by two 12Gy doses of photon or proton radiation. Intraperitoneal injection of 200 μg αPD1 was performed on days 7, 10, 14, 21, 28, 35, and 42. Tumor volumes were compared using 2-way ANOVA, and mouse survival rates were assessed using the Kaplan–Meier method, with differences compared via log-rank tests. The count of lung metastases was compared using 2-tailed t-tests. Data are displayed as mean ± SEM. Statistical significance was set at P < 0.05. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001. NS, not significant