This randomized prospective open-label phase 2 trial testes the safety and feasibility of a hypofractionated accelerated neoadjuvant proton or carbon ion radiotherapy based on the rate of wound healing disorders from beginning of radiotherapy to maximum 120 days after the planned tumor resection or discontinuation of treatment due to any reason. The treatment is of shorter duration (2-3 weeks vs. 5 weeks standard treatment), which should please most patients and thus enhance quality of life. The treatment regimen furthermore promises a reduced rate of late side effects and significant optimization of the current treatment standards. A phase II trial is mandatory not only for obtaining the safety and feasibility data, but also in order to prepare a concurrent phase III trial. Due to the low incidence of soft tissue sarcoma, only a well prepared multicenter study has a chance to be successfully completed based on previous experiences in trials for seldom tumor entities.