Carbon Ion Radiotherapy in Hypofraction Regimen for Stage 1Non-Small Cell Lung Cancer

From 1994 to 1999, we conducted a phase I/II clinical trial for stage I non-small cell lung cancer (NSCLC) by using carbon ion beams alone, demonstrating optimal doses of 90.0GyE in 18 fractions over 6 weeks and 72.0GyE in 9 fractions over 3 weeks for achieving more than 95% local control with minimal pulmonary damage. In the present study, the total dose was fixed at 72.0GyE in 9 fractions over 3 weeks, and at 52.8GyE for stage IA and 60.0GyE for stage 1B in 4 fractions over 1 week. Following this schedule, we conducted a phase II clinical trial for stage I NSCLC from 1999 to 2003. We also conducted a phase I/II single fractionation clinical trial that was a dose escalation study. The total dose was initially 28.0GyE in 2003 and was raised to 44.0GyE in 2007. This article describes the intermediate steps. Most targets were irradiated from four oblique directions. A respiratory-gated irradiation system was used for all sessions. Local control and survival were assessed by the Kaplan-Meier method. For statistical testing, the Long-rank test was used.The local control rate for all patients was 91.5%, and those for T1 and T2 tumors were 96.3% and 84.7%, respectively. While there was a significant difference (p=0.0156) in tumor control rate between T1 and T2, there was no significant difference (P=0.1516) between squamous cell carcinomas and non-squamous cell carcinomas. The five-year cause-specific survival rate was 67.0% (IA: 84.4, IB: 43.7), and overall survivals were 45.3% (IA: 53.9, 1B: 34.2). No adverse effects greater than grade 3 occurred in the lung. In a single fractionation trial, the local control rate for all 72 patients was 89.3%, and the control rates for T1 and T2 tumors were 94.6% and 78.7%, respectively. No adverse effects greater than grade 3 occurred in the lung. Carbon beam radiotherapy, an excellent new modality in terms of high QOL and ADL, was proven to be a valid alternative to surgery for stage I cancer, especially for elderly and inoperable patients.NIRS-MD Anderson Symposium on Clinical Issues for Particle Therap