You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
High control rate in patients with chondrosarcoma of the skull base after carbon ion therapy: First report of long‐term results
Abstract 1:
The current study was performed to evaluate the safety and effectiveness of irradiation with carbon ions using raster scanning as well as prognostic factors in patients with skull base chondrosarcomas


Title 2:
Carbon ion radiotherapy of skull base chondrosarcomas.
Abstract 2:
PURPOSE To evaluate the effectiveness and toxicity of carbon ion radiotherapy in chondrosarcomas of the skull base . PATIENTS AND METHODS Between November 1998 and September 2005 , 54 patients with low- grade and intermediate- grade chondrosarcomas of the skull base have been treated with carbon ion radiation therapy ( RT ) using the raster scan technique at the Gesellschaft für Schwerionenforschung in Darmstadt , Germany . All patients had gross residual tumors after surgery . Median total dose was 60 CGE ( weekly fractionation 7 x 3.0 CGE ) . All patients were followed prospect ively in regular intervals after treatment . Local control and overall survival rates were calculated using the Kaplan-Meier method . Toxicity was assessed according to the Common Terminology Criteria ( CTCAE v.3.0 ) and the Radiation Therapy Oncology Group (RTOG)/European Organization for Research and Treatment of Cancer ( EORTC ) score . RESULTS Median follow-up was 33 months ( range , 3 - 84 months ) . Only 2 patients developed local recurrences . The actuarial local control rates were 96.2 % and 89.8 % at 3 and 4 years ; overall survival was 98.2%at 5 years . Only 1 patient developed a mucositis CTCAE Grade 3 ; the remaining patients did not develop any acute toxicities > CTCAE Grade 2 . Five patients developed minor late toxicities ( RTOG/EORTC Grade s 1 - 2 ) , including bilateral cataract ( n = 1 ) , sensory hearing loss ( n = 1 ) , a reduction of growth hormone ( n = 1 ) , and asymptomatic radiation-induced white matter changes of the adjacent temporal lobe ( n = 2 ) . Grade 3 late toxicity occurred in 1 patient ( 1.9 % ) only . CONCLUSIONS Carbon ion RT is an effective treatment for low- and intermediate- grade chondrosarcomas of the skull base offering high local control rates with low toxicity


Title 3:
Carbon ion radiotherapy performed as re-irradiation using active beam delivery in patients with tumors of the brain, skull base and sacral region.
Abstract 3:
INTRODUCTION To asses carbon ion radiation therapy ( RT ) performed as re-irradiation in 28 patients with recurrent tumors . MATERIAL S AND METHODS Twenty-eight patients were treated with carbon ion RT as re-irradiation for recurrent chordoma and chondrosarcoma of the skull base ( n=16 and n=2 ) , one chordoma and one chondrosarcoma of the os sacrum , high-risk meningioma ( n=3 ) , adenoid-cystic carcinoma ( n=4 ) as well as one SCCHN . All patients were treated using active raster scanning , and treatment planning was performed on CT- and MRI-basis . All patients were followed prospect ively during follow-up . RESULTS In all patients re-irradiation could be applied safely without interruptions . For skull base tumors , local tumor control after re-irradiation was 92 % at 24 months and 64 % at 36 months . Survival after re-irradiation was 86 % at 24 months , and 43 % at 60 months . In all three meningiomas treated with C12 for re-irradiation , the tumor recurrence was located within the former RT-field . Two patients developed tumor progression at 6 months , and in one patient the tumor remained stable for 67 months . In patients with head- and -neck tumors , three patients developed local tumor progression at 12 , 24 and 29 months after re-irradiation . Median local progression-free survival was 24 months . For sacral tumors , re-irradiation offered palliation with tumor control for 24 and 36 months . CONCLUSION Due to the physical characteristics particle therapy offers a new treatment modality in cases with tumor recurrences . With carbon ions , the additional biological benefits may be exploited for long-term tumor control . Further evaluation in a larger patients ' cohort will be performed in the future


Title 4:
Radiotherapy for chordomas and low-grade chondrosarcomas of the skull base with carbon ions.
Abstract 4:
PURPOSE Compared to photon irradiation , carbon ions provide physical and biologic advantages that may be exploited in chordomas and chondrosarcomas . METHODS AND MATERIAL S Between August 1998 and December 2000 , 37 patients with chordomas ( n = 24 ) and chondrosarcomas ( n = 13 ) were treated with  carbon ion radiotherapy  within a Phase I/II trial . Tumor conformal application of carbon ion beams was realized by intensity-controlled raster scanning with pulse-to-pulse energy variation . Three-dimensional treatment planning included biologic plan optimization . The median tumor dose was 60 GyE ( GyE = Gy x relative biologic effectiveness ) . RESULTS The mean follow-up was 13 months . The local control rate after 1 and 2 years was 96 % and 90 % , respectively . We observed 2 recurrences outside the gross tumor volume in patients with chordomas . Progression-free survival was 100 % for chondrosarcomas and 83 % for chordomas at 2 years . Partial remission after  carbon ion radiotherapy  was observed in 6 patients . Treatment toxicity was mild . CONCLUSION These are the first data demonstrating the clinical feasibility , safety , and effectiveness of scanning beam delivery of ion beams in patients with skull base tumors . The preliminary results in patients with skull base chordomas and low- grade chondrosarcomas are encouraging , although the follow-up was too short to draw definite conclusions concerning outcome . In the absence of major toxicity , dose escalation might be considered
The emerging use of CIRT to treat skull base chordomas and chondrosarcomas appear promising with regard to tumor control , overall survival , and risk profile of early and late toxicity .