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:
RADIOSURGERY WITH THE WORLD'S FIRST FULLY ROBOTIZED LEKSELL GAMMA KNIFE PERFEXION IN CLINICAL USE: A 200‐PATIENT PROSPECTIVE, RANDOMIZED, CONTROLLED COMPARISON WITH THE GAMMA KNIFE 4C
Abstract 1:
OBJECTIVE The world 's first Leksell Gamma Knife PerfeXion ( Elekta Instrument AB , Stockholm , Sweden ) for radiosurgery of the head and neck became operational at Timone University Hospital in Marseille on July 10 , 2006 . To allow strict evaluation of the capabilities , advantages , disadvantages , and limitations of this new technology , patients were enrolled in a prospect i ve , r and omized trial . METHODS In 66 working days , between July 10 and December 20 , 2006 , 363 patients were treated by gamma knife surgery at Timone University Hospital , Marseille . Of these patients , 200 were eligible for the comparative prospect i ve study ( inclusion criteria were informed consent obtained , tumor or vascular indication , and no previous radiosurgery or radiotherapy ) . In accordance with the blinded r and omization process , 100 patients were treated with the Leksell Gamma Knife 4C ( Elekta Instrument AB ) and Gamma Knife 100 ( Elekta Instrument AB ) with the Leksell Gamma Knife PerfeXion .  Dose planning parameters , dosimetry measurements on the patient 's body , workflow , patient comfort , quality assurance procedure , and a series of other treatment-related parameters were systematic ally and prospect ively evaluated in both arms of the trial . RESULTS No technical failure of the treatment procedure was encountered . The new dose-planning system led to the use of composite shots in 39.4 % of the patients . The median number of different collimator sizes used was larger with the PerfeXion than with the 4C ( 2 and 1 , respectively ) . The mean number of isocenters used was lower ( 10.67 and 13.08 , respectively ) . The median total treatment time was significantly shorter with the PerfeXion ( 40 and 60 minutes , respectively ) , but there was no significant difference in the median radiation time ( 34.02 and 33.40 minutes , respectively ) . The procedure was performed using only a single run in 98.99 % of the PerfeXion cases and in 42 % of the 4C cases . Collision risk on the 4C forced us to change the frame gamma angle for at least 1 shot in 24 % of the patients and led to treatment in manual mode for at least 1 shot in 21 % of the patients . Collision risk requiring technical adaptation did not occur with the PerfeXion . In 1 patient treated with the PerfeXion , the system required a direct collision check . In terms of dose to structures outside the target area , the PerfeXion delivers 8.2 times less to the vertex , 10 times less to the thyroid , 12.9 times less to the sternum , and 15 times less to the gonads . CONCLUSION Our prospect i ve study indicates that procedures with the PerfeXion were collision-free , even with very eccentric lesions ( e.g. , multiple metastases ) . The duration of the surgical procedure , the amount of time required for nurse , physicist , and physician intervention on the machine , and the duration of the quality assurance procedure were all shown to be dramatically reduced with the PerfeXion gamma knife . Patient protection is greatly improved with the PerfeXion . In our experience , the technological advances of the Leksell Gamma Knife PerfeXion will make a very significant contribution to future progress in head and neck radiosurgery


Title 2:
Acoustic neuroma: potential benefits of fractionated stereotactic radiosurgery.
Abstract 2:
BACKGROUND Single-fraction radiosurgery of acoustic neuromas less than 3 cm in diameter is remarkable for high control but not infrequent incidence of facial and trigeminal neuropathy . Larger tumors treated surgically often result in deafness and facial neuropathy . Fractionated stereotactic radiosurgery was used in an effort to maintain effective therapy while minimizing toxicity of treatment . METHODS The authors described 38 patients with acoustic neuromas , with age range 35 - 89 years ( mean , 60 years ) .  2,000 cGy in divided weekly doses of 400 or 500 cGy was most commonly prescribed . Tumors > or = 3 cm ( n = 16 ) received the 5 fraction schema . Mean tumor volume was 6.9 cm3 , with range from 0.1 to 32.0 cm3 . RESULTS Median clinical follow-up was 27.1 months , while neuroimaging follow-up had a median of 16.3 months . All tumors were controlled . Of 23 tumors smaller than 3 cm , 14 ( 61 % ) decreased in size , and 9 showed cessation of growth . Thirteen of 16 ( 81 % ) large acoustic neuromas ( 3 - 5 cm ) diminished in size . The remaining 3 showed cessation of growth . Median radiographic follow-up was 20 months , with a median clinical follow-up of 28 months . No patient developed fifth nerve symptoms after treatment nor did any patient require surgery for treatment failure . Only one had temporary seventh nerve palsy . CONCLUSION Fractionated stereotactic radiosurgery offers a therapeutic approach producing high control rates while avoiding morbidity frequently seen after single-fraction radiosurgery or microsurgery


Title 3:
Growth of untreated vestibular schwannoma: a prospective study.
Abstract 3:
OBJECT Small vestibular schwannomas ( VSs ) are often conservatively managed and treated only upon growth . Growth is usually reported in mm/year , but describing the growth of a 3D structure by a single diameter has been question ed . As a result , VS growth dynamics should be further investigated . In addition , baseline clinical parameters that could predict growth would be helpful . In this prospect i ve study the authors aim ed to describe growth dynamics in a cohort of conservatively managed VSs . They also compared different growth models and evaluated the ability of baseline parameters to predict future growth . METHODS Between 2000 and 2006 , 178 consecutive patients with unilateral de novo small-sized VSs identified among the Norwegian population of 4.8 million persons were referred to a tertiary care center and were included in a study protocol of conservative management . Tumor size was defined by MR imaging-based volume estimates and was recorded along with clinical data at regular visits . Mixed-effects models were used to analyze the relationships between observations . Three growth models were compared using statistical diagnostic tests : a mm/year-based model , a cm(3)/year-based model , and a  volume doubling time  (VDT)-based model . A receiver operating characteristic curve analysis was used to determine a cutoff for the VDT-based model for distinguishing growing and nongrowing tumors . RESULTS A mean growth rate corresponding to a VDT of 4.40 years ( 95 % CI 3.49 - 5.95 ) was found . Other growth models in this study revealed mean growth rates of 0.66 mm/year ( 95 % CI 0.47 - 0.86 ) and 0.19 cm(3)/year ( 95 % CI 0.12 - 0.26 ) . Volume doubling time was found to be the most realistic growth model . All baseline variables had p values > 0.09 for predicting growth . CONCLUSIONS Based on the actual measurements , VDT was the most correct way to describe VS growth . The authors found that a cutoff of 5.22 years provided the best value to distinguish growing from nongrowing tumors . None of the investigated baseline predictors were usable as predictors of growth


Title 4:
Patient outcomes after vestibular schwannoma management: a prospective comparison of microsurgical resection and stereotactic radiosurgery.
Abstract 4:
OBJECTIVE The best management for patients with small- to medium-sized vestibular schwannomas ( VS ) is controversial . METHODS : A prospect i ve cohort study of 82 patients with unilateral , unoperated VS less than 3 cm undergoing surgical resection ( n = 36 ) or radiosurgery ( n = 46 ) . Patients undergoing resection were younger ( 48.2 yr versus 53.9 yr , P = 0.03 ) . The groups were similar with regard to hearing loss , associated symptoms , and tumor size . The mean follow-up period was 42 months ( range , 12 - 62 mo ) . RESULTS Normal facial movement and preservation of serviceable hearing was more frequent in the radiosurgical group at 3 months ( P < 0.001 ) , 1 year ( P < 0.001 ) , and at the last follow-up examination ( P < 0.01 ) compared with the surgical resection group . Patients undergoing surgical resection had a significant decline in the following subscales of the Health Status Question naire 3 months after surgery : physical functioning ( P = 0.006 ) , role-physical ( P < 0.001 ) , energy/fatigue ( P = 0.02 ) , and overall physical component ( P = 0.004 ) . Patients in the surgical resection group continued to have a significant decline in the physical functioning ( P = 0.04 ) and bodily pain ( P = 0.04 ) subscales at 1 year and in bodily pain ( P = 0.02 ) at the last follow-up examination . The radiosurgical group had no decline on any component of the Health Status Question naire after the procedure . The radiosurgical group had lower mean Dizziness H and icap Inventory scores ( 16.5 versus 8.4 , P = 0.02 ) at the last follow-up examination . There was no difference in tumor control ( 100 versus 96 % , P = 0.50 ) . CONCLUSION Early outcomes were better for VS patients undergoing stereotactic radiosurgery compared with surgical resection ( Level 2 evidence ) . Unless long-term follow-up evaluation shows frequent tumor progression at currently used radiation doses , radiosurgery should be considered the best management strategy for the majority of VS patients


Title 5:
Conservative management or gamma knife radiosurgery for vestibular schwannoma: tumor growth, symptoms, and quality of life.
Abstract 5:
BACKGROUND There are few reports about the course of vestibular schwannoma ( VS ) patients following gamma knife radiosurgery ( GKRS )  compared with the course following conservative management ( CM ) . In this study , we present prospect ively collected data of 237 patients with unilateral VS extending outside the internal acoustic canal who received either GKRS ( 113 ) or CM ( 124 ) . OBJECTIVE The aim was to measure the effect of GKRS compared with the natural course on tumor growth rate and hearing loss . Secondary end points were post inclusion additional treatment , quality of life ( QoL ) , and symptom development . METHODS The patients underwent magnetic resonance imaging scans , clinical examination , and QoL assessment by SF-36 question naire . Statistics were performed by using Spearman correlation coefficient , Kaplan-Meier plot , Poisson regression model , mixed linear regression models , and mixed logistic regression models . RESULTS Mean follow-up time was 55.0 months ( 26.1 st and ard deviation , range 10 - 132 ) . Thirteen patients were lost to follow-up . Serviceable hearing was lost in 54 of 71 ( 76 % ) ( CM ) and 34 of 53 ( 64 % ) ( GKRS ) patients during the study period ( not significant , log-rank test ) . There was a significant reduction in tumor volume over time in the GKRS group . The need for treatment following initial GKRS or CM differed at highly significant levels ( log-rank test , P < .001 ) . Symptom and QoL development did not differ significantly between the groups . CONCLUSION In VS patients , GKRS reduces the tumor growth rate and thereby the incidence rate of new treatment about tenfold . Hearing is lost at similar rates in both groups . Symptoms and QoL seem not to be significantly affected by GKRS


Title 6:
VESTIBULAR SCHWANNOMA: SURGERY OR GAMMA KNIFE RADIOSURGERY? A PROSPECTIVE, NONRANDOMIZED STUDY
Abstract 6:
OBJECTIVE To conduct a prospect i ve , open , nonr and omized study of treatment-associated morbidity in patients undergoing microsurgery or gamma knife radiosurgery ( GKRS ) for vestibular schwannomas . METHODS Ninety-one patients with vestibular schwannomas with a maximum tumor diameter of 25 mm in the cerebellopontine angle were treated according to a prospect i ve protocol either by  GKRS  ( 63 patients ) or open microsurgery ( 28 patients ) using the suboccipital approach . Primary end points included hearing function , according to the Gardner-Robertson scale , and facial nerve function , according to the House-Brackmann scale at 2 years . Clinical data included a balance platform test , score for tinnitus and vertigo using a visual analog scale , and working ability . Patients responded to the quality -of-life question naires Short-Form 36 and Glasgow Benefit Inventory . RESULTS Three elderly GKRS patients withdrew ; all remaining patients were followed for 2 years . Both primary end points were highly significant in favor of GKRS ( P < 0.001 ) . Evidence of reduced facial nerve function ( House-Brackmann grade 2 or poorer ) at 2 years was found in 13 of 28 open microsurgery patients and 1 of 60 GKRS patients . Thirteen of 28 patients who underwent surgery had serviceable hearing ( Gardner-Robertson grade A or B ) preoperatively , but none had serviceable hearing postoperatively . Twenty-five of 60 GKRS patients had serviceable hearing before treatment , and 17 ( 68 % ) of them had serviceable hearing 2 years after treatment . The tinnitus and vertigo visual analog scale score , as well as balance platform tests , did not change significantly after treatment , and working status did not differ between the groups at 2 years . Quality of life was significantly better in the GKRS group at 2 years , based on the Glasgow Benefit Inventory question naire . One GKRS patient required operative treatment within the 2-year study period . CONCLUSION This is the second prospect i ve study to demonstrate better facial nerve and hearing outcomes from GKRS than from open surgery for small- and medium-sized vestibular schwannomas
There is no high quality evidence in the literature from RCTs to determine whether  stereotactic radiotherapy  is better than  microsurgical resection or observation alone  for patients with a vestibular schwannoma .