Curative treatment of stage I non-small-cell lung cancer with carbon ion beams using a hypofractionated regimen

Purpose: A phase I/II study on carbon ion radiotherapy for stage I non-small cell lung cancer (NSCLC) was first conducted from 1994 to 1999 and determined the optimal dose. Second, a phase II study using the optimal dose was performed. The purpose of the present study was to clarify the local control and 5-year survival rates.Methods and Materials: From April 1999 to December 2000, 50 patients with 51 primary lesions were treated. Using a fixed dose of 72GyE in 9 fractions over 3 weeks, the primary tumors were irradiated with carbon ion beams alone. The average age of the patients was 74.5 years. Thirty three (66%) of them were medically inoperable. Local control and survival were determined by using the Kaplan-Meier method and the data were statistically processed by using the long-rank test.Results: All patients were observed for a minimum of 5 years or until death with a median follow-up time of 59.2 months ranging from 6.0 months to 83.0 months. The local control rate for all patients was 94.7%. The patients five-year cause-specific survival rate was 75.7% (IA: 89.4 IB: 55.1), and overall survival 50.0% (IA: 55.2, IB: 42.9). No toxic reactions in the lung greater than grade 3 were detected.Conclusions: Carbon ion radiotherapy, a new treatment modality with superior benefits in terms of QOL and ADL, has been proven as a valid alternative to surgery for stage I NSCLC and to offer particular benefits especially for elderly and inoperable patients