Carbon Ion Radiotherapy in a Hypofractionated Regimen for　Stage I Non-Small Cell Lung Cancer

AbstractBeginning in 1994, 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 90.0 GyE in 18 fractions over six weeks and 72.0 GyE in nine fractions over three weeks for achieving more than 95% local control with minimal pulmonary damage. Following this schedule, we conducted phase II clinical trials for stage I NSCLC from 1999 to 2003. In the present study, the total dose was fixed at 72.0 GyE in nine fractions over three weeks, and at 52.8 GyE for stage IA and 60.0 GyE for stage 1B in four fractions in one week. We also conducted a phase I/II single fractionation clinical trial as a dose escalation study. The total dose was increased from 28.0 GyE to 50.0 GyE. In the first and second phase II trials, the local control rate for all patients was 91.5%, and those for patients with T1 and T2 tumors were 96.3% and 84.7%, respectively. The five-year overall survival rate was 45.3%. No adverse effects greater than grade 2 occurred in the lung. In a single fractionation trial, the five-year local control rate for 151 patients was 79.2%, and the control rates for T1 and T2 tumors were 83.6% and 72.2%, respectively. No adverse effects greater than grade 2 occurred in the lung. Carbon beam radiotherapy, an excellent new modality in terms of a high quality of life and activities of daily living, was proven to be a valid alternative to surgery for patients with stage I cancer, especially for elderly and inoperable patients