@misc{oai:repo.qst.go.jp:00064874,
 author = {Tsuji, Hiroshi and Kamada, Tadashi and Nomiya, Takuma and Tsujii, Hirohiko and 辻 比呂志 and 鎌田 正 and 野宮 琢磨 and 辻井 博彦},
 month = {Dec},
 note = {1. Introduction
 The NIRS has been challenging the prostate cancer treatment from June 1995 taking the advantage of the quality of carbon ion beam which has distinguished dose convergence and high anticancer efficacy. The safety and efficacy of C-ion RT was confirmed with clinical studies, and government approval for its use as an advanced medicine was obtained in November 2003. 
2. Materials and methods
  A total of 1,593 prostate cancer patients have received carbon ion radiotherapy from the start of clinical trial to July 2012. We treated 96 cases in the early dose escalation trials, 175 cases in the phase II clinical trial, thereafter 1,322 cases were treated.  The annual cases are gradually increasing, especially greatly increased in 2003 when we gained the government approval of advanced medicine and in 2007 when we shortened the therapy term from 20 fractions in 5 weeks to 16 fractions in 4 weeks.  
When we started the phase II study, the irradiated dose was fixed at 63.0GyE or 66.0GyE/20fractions as the recommended dose fractionation schedule established in the two previous phase I/II studies. In addition, more hypofractionated schedule of 57.6GyE/16fractionas was applied since September 2007. Furthermore, a new clinical trial of C-ion RT of 12 fractions over 3 weeks was also conducted in 2010. In the near future all prostate cancer patients will be treated with 12-fraction carbon ion therapy.
3. Results
 As for the treatment morbidity, in the lower urinary tract, the incidence of grade 2 or worse late toxicity was approximately the same in 63.0GyE/20fractions carbon ion radiotherapy, intensity modulated radiation therapy and proton, which is interesting that it shows that this dose has comparable impact against lower urinary tract tissues. While for the 57.6GyE/16 fractions, the lowering of incidence was realized as a real outcome for shortening the treatment term. As for the rectal toxicity, even 63.0GyE showed lower rate than X-ray or proton, this is thought to be the proof of eminent dose convergence of carbon ion beam. In addition, 57.6GyE gained further lowering. Adding shortening to the high dose convergence, significant reduction of toxicity was obtained.   
 Regarding the antitumor effect, especially in the high-risk groups, high survival rate was gained. It is caused by the carbon ion's excellent curative effect along with the distinguished treatment strategy.  There was no difference in relapse-free rate and survival rate between 20 fractions and 16 fractions, while the result showed that the toxicity was less in 16 fractions. Therefore reducing the fractions to 16 made it possible to achieve not only the improvement of efficiency but also the improvement of outcome from therapy.
Recently the pencil beam scanning irradiation has become available. Comparing the dose-volume of the rectum with scanning irradiation to that of passive irradiation in the treatment of prostate cancer, better rectum sparing can be obtained with scanning , though the difference is not large. Therefore, scanning irradiation was started to apply to the prostate cancer patients and will be applied to all the prostate cancer in the near future., MMND & IPCT Workshop},
 title = {Carbon ion radiotherapy for prostate cancer},
 year = {2012}
}