Carbon ion radiotherapy for malignant head-and-neck tumors

The purpose of this study was to evaluate the efficacy of carbon ion radiotherapy for malignant head-and-neck tumors. Between April 1997 and February 2011, 407 cases with locally advanced, histologically proven, and primary or recurrent malignant tumors of the head-and-neck were treated with carbon ions. Treatment dose was 64.0 GyE in 16 fractions over 4 weeks (or 57.6 GyE when a wide area of skin was included in the target volume). There were no acute reactions worse than grade 3 and no late toxicities worse than grade 2. The five-year local control and overall survival rates were 73% and 53%, respectively. But the five-year local control rate was 24% for bone and soft tissue sarcomas, and the five-year overall survival rate was 35% for malignant melanomas. Carbon ion radiotherapy for malignant head-and-neck tumors can be described as presenting no clinical problems. Although local control of carbon ion radiotherapy was promising for malignant head-and-neck tumor excluding sarcoma, the survival rate was not commensurate with the favorable local control rate of malignant melanoma. On the basis of the results of the analysis, this part of the study was divided into two additional protocols, one for bone and soft tissue sarcomas and another for mucosal malignant melanomas. (author)