@inproceedings{oai:repo.qst.go.jp:00054430,
 author = {Tsuji, Hiroshi and Nomiya, Takuma and Maruyama, Katsuya and Kamada, Tadashi and Tsujii, Hirohiko and 辻 比呂志 and 野宮 琢磨 and 丸山 克也 and 鎌田 正 and 辻井 博彦},
 book = {NIRS＆MedAustron　Joint Symposium on Carbon Ion Radiotherapy},
 month = {Dec},
 note = {Abstract：
A clinical trial of carbon ion radiotherapy (C-ion RT) for prostate cancer was started in 1995 at the National Institute of Radiological Sciences (NIRS), taking advantage of the quality of carbon ion beams to distinguish dose concentrations and establish a high anticancer efficacy.  First, two phase I/II dose escalation studies with a fractionation of 20 fractions over five weeks were conducted to establish techniques using carbon ion beams to determine the optimal dose of fractionation. Then, a phase II study of 20 fractions was performed to validate the feasibility and efficacy of C-ion RT delivered in 20 fractions, which was successfully completed in 2003. Thereafter, a study of hypofractionated C-ion RT in16 fractions over four weeks was performed. Consequently, the incidence of late radiation toxicity decreased without an increase in tumor recurrence. Currently, hypofractionated radiotherapy in 12 fractions over three weeks with scanning irradiation is being evaluated in clinical practice. 
Up to February 2013, 1,733 patients underwent C-ion RT, including 552 patients treated with 20 fractions, 1,107 patients treated with 16 fractions, and 64 patients treated with 12 fractions. Of these patients, 53% were categorized as high-risk. The five-year overall survival rate and biochemical relapse-free rate in the entire group were 95.1% and 90.7%, respectively. All risk factors had a significant influence on both biochemical control and patient survival. Biochemical control was not affected by the alteration of dose fractionation; however, the incidence of late radiation toxicity decreased in association with a decrease in the fraction number.},
 pages = {32--37},
 title = {Carbon Ion Radiotherapy in Patients with Prostate Cancer},
 year = {2013}
}