***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE Cerebral low- grade gliomas ( LGG ) in adults are mostly composed of astrocytomas , oligodendrogliomas , and mixed oligoastrocytomas . There is at present no consensus in the policy of treatment of these tumors . We sought to determine the efficacy of radiotherapy and the presence of a dose-response relationship for these tumors in two multicentric r and omized trials conducted by the European Organization for Research and Treatment of Cancer ( EORTC ) . The dose-response study is the subject of this article . METHODS AND MATERIAL S For the dose-response trial , 379 adult patients with cerebral LGGs were r and omized central ly at the EORTC Data Center to receive irradiation postoperatively ( or postbiopsy ) with either 45 Gy in 5 weeks or 59.4 Gy in 6.6 weeks with quality -controlled radiation therapy . All known parameters with possible influences on prognosis were prospect ively recorded . Conventional treatment techniques were recommended . RESULTS With 343 ( 91 % ) eligible and evaluable patients followed up for at least 50 months with a median of 74 months , there is no significant difference in terms of survival ( 58 % for the low-dose arm and 59 % for the high-dose arm ) or the progression free survival ( 47 % and 50 % ) between the two arms of the trial . However , this prospect i ve trial has revealed some important facets about the prognostic parameters : The T of the TNM classifications as proposed in the protocol appears to be one of the most important prognostic factors ( p < 0.0001 ) on multivariate analysis . Other prognostic factors , most of which are known , have now been quantified and confirmed in this prospect i ve study . CONCLUSION The EORTC trial 22844 has not revealed the presence of radiotherapeutic dose-response for patients with LGG for the two dose levels investigated with this conventional setup , but objective prognostic parameters are recognized . The tumor size or T parameter as used in this study appears to be a very important factor PURPOSE To compare survival and toxicity in adult patients treated with low-dose ( 50.4 Gy/28 fractions ) versus high-dose ( 64.8 Gy/36 fractions ) localized radiation therapy ( RT ) for supratentorial low- grade astrocytoma , oligodendroglioma , and mixed oligoastrocytoma . PATIENTS AND METHODS From 1986 to 1994 , 203 eligible/analyzable patients were r and omized : 101 to low-dose RT , 102 to high-dose RT . Almost half were younger than 40 years , and 95 % had grade 2 tumors . Histologic subtype was astrocytoma ( or mixed oligo-astrocytoma with astrocytoma dominant ) in 32 % of patients and oligodendroglioma ( or oligoastrocytoma with oligodendroglioma dominant ) in 68 % . Tumor diameter was less than 5 cm in 35 % of patients , and 41 % of tumors showed some degree of contrast enhancement . Extent of resection was gross total in 14 % of patients , subtotal in 35 % , and biopsy only in 51 % . RESULTS At the time of the present analysis , 83 patients ( 41 % ) are dead , and median follow-up is 6.43 years in the 120 who are still alive . Survival at 2 and 5 years is nonsignificantly better with low-dose RT ; survival at 2 and 5 years was 94 % and 72 % , respectively , with low-dose RT and 85 % and 64 % , respectively , with high-dose RT ( log rank P = .48 ) . Multivariate analysis identified histologic subtype , tumor size , and age as the most significant prognostic factors . Survival is significantly better in patients who are younger than 40 years and in patients who have oligodendroglioma or oligo-dominant histology . Grade 3 to 5 radiation neurotoxicity ( necrosis ) was observed in seven patients , with one fatality in each treatment arm . The 2-year actuarial incidence of grade 3 to 5 radiation necrosis was 2.5 % with low-dose RT and 5 % with high-dose RT . CONCLUSION This phase III prospect i ve r and omized trial of low- versus high-dose radiation therapy for adults with supratentorial low- grade astrocytoma , oligodendroglioma , and oligoastrocytoma found somewhat lower survival and slightly higher incidence of radiation necrosis in the high-dose RT arm . The most important prognostic factors for survival are histologic subtype , tumor size , and age . The study design of the ongoing intergroup trial in this population will be discussed We report the prognostic significance of tumor CT contrast enhancement within histological subgroups in 831 consecutive adult glioma patients of high- grade ( n=516 ) and low- grade ( n=315 ) histology . In the present report , a negative prognostic factor is associated with shortened survival . Methods : Survival analysis including Kaplan-Meier plots , log-rank tests , Cox analysis , and Aalen 's linear model as implemented in SPSS and S-PLUS . Results : Sensitivity and specificity of contrast enhancement as a test for high- grade glioma was 0.87 and 0.79 , respectively . Enhancement was a strong negative prognostic factor comparable to high- grade histology in the total patient population . Enhancement was also a negative prognostic factor within the subgroups adult high- grade ( Grade 3–4 ) , anaplastic ( Grade 3 ) , and low- grade ( Grade 1–2 ) gliomas ( p < 0.001 ) . The prognostic implication s of initial enhancement declined in high- grade patients surviving beyond 36 months .  Tumor contrast enhancement or calcifications  ( in parentheses ) were present in 96 % ( 3.6 % ) of glioblastomas , in 87 % ( 7.4 % ) of high- grade gliomas , in 56.5 % of anaplastic gliomas , and in 21 % ( 16.2 % ) of low- grade gliomas . Calcification was a positive prognostic factor within the high- grade group of patients ( p < 0.0001 ) . Conclusion : Enhancement was a major prognostic factor comparable to high- grade histology in this glioma patient population . Enhancement was a negative prognostic factor within each of the adult subgroups high- grade , anaplastic ( grade 3 ) , and low- grade gliomas . Enhancement was strongly associated with but not pathognomonic for high- grade histology Summary . Background : Patients with radiologically ( MRI and /or CT images ) suspected malignant glioma is referred to radiotherapy after craniotomy and resection of the tumour or after diagnostic biopsy .  Patients with poor preoperative status and elderly patients are diagnosed more often by biopsy and treated by radiotherapy rather than by craniotomy and tumour resection . However , based on previous retrospective studies it is not possible to conclude which procedure is better for elderly patients . Thus a prospect i ve study comparing these two procedures with elderly patients was planned . Methods : 30 patients older than 65 years with radiologically ( CT and /or MRI ) obvious malignant glioma were r and omised into two groups : I ) stereotactic biopsy and II ) open craniotomy and resection of the tumour .  Nineteen patients were diagnosed to have grade IV glioma and four patients grade III glioma . Seven out of 30 ( 23 % ) were followed in the “ intention-to-treat ” group with diagnosis of stroke ( n=3 ) , metastasis ( n=2 ) , malignant lymphoma ( n=1 ) and one with out histological diagnosis . Patients with histologically verified malignant glioma ( grade III – IV ) were diagnosed by stereotactic biopsy ( n=13 ) or by open craniotomy and resection ( n=10 ) and all the patients were referred to radiotherapy .  Survival and time of deterioration were followed . Findings : The overall median survival time was 146 ( 95 % CI 89–175 ) days after the procedure . The estimated median survival time was 171 ( 95 % CI 146–278 ) days after the craniotomy versus 85 ( 95 % CI 55–157 ) days after the biopsy ( p=0.035 ) . The estimated survival time was 2.757 times longer ( 95 % CI 1.004–7.568 , p=0.049 ) after craniotomy . However , there was no significant difference in the time of deterioration between these two treatments ( p=0.057 ) . Amount of radiotherapy  given had a significant effect on survival ( p=0.001 ) . Interpretation : Longer survival time is achieved after open craniotomy and resection of tumour . However , overall benefit of open surgery to patient seems to be modest , while time of deterioration did not differ between two treatment groups . Our results support previous studies on the benefit of radiotherapy in the treatment of malignant glioma OBJECTIVE To evaluate diffusion tensor imaging (DTI)-based functional neuronavigation in surgery of cerebral gliomas with pyramidal tract ( PT ) involvement with respect to both perioperative assessment and follow-up outcome . METHODS A prospect i ve , r and omized controlled study was conducted between 2001 and 2005 . A consecutive series of 238 eligible patients with initial imaging diagnosis of cerebral gliomas involving PTs were r and omized into study ( n = 118 ) and control ( n = 120 ) groups . The study cases underwent DTI and three-dimensional magnetic resonance imaging scans . The maps of fractional anisotropy were calculated for PT mapping . Both three-dimensional magnetic resonance imaging data sets and fractional anisotropy maps were integrated by rigid registration , after which the tumor and adjacent PT were segmented and reconstructed for presurgical planning and intraoperative guidance . The control cases were operated on using routine neuronavigation . RESULTS There was a trend for high- grade gliomas ( HGGs ) in the study group to be more likely to achieve gross total resection ( 74.4 versus 33.3 % , P < 0.001 ) . There was no significant difference of low- grade gliomas resection between the two groups . Postoperative motor deterioration occurred in 32.8 % of control cases , whereas it occurred in only 15.3 % of the study cases ( P < 0.001 ) . The 6-month Karnofsky Performance Scale score of study cases was significantly higher than that of control cases ( 86 ± 20 versus 74 ± 28 overall , P < 0.001 ; 93 ± 10 versus 86 ± 17 for low- grade gliomas , P = 0.013 ; and 77 ± 27 versus 53 ± 32 for HGGs , P = 0.001 ) . For 81 HGGs , the median survival of study cases was 21.2 months ( 95 % confidence interval , 14.1–28.3 mo ) compared with 14.0 months ( 95 % confidence interval , 10.2–17.8 mo ) of control cases ( P = 0.048 ) . The estimated hazard ratio for the effect of DTI-based functional neuronavigation was 0.570 , representing a 43.0 % reduction in the risk of death . CONCLUSION DTI-based functional neuronavigation contributes to maximal safe resection of cerebral gliomas with PT involvement , thereby decreasing postoperative motor deficits for both HGGs and low- grade gliomas while increasing high- quality survival for HGGs OBJECTIVE A prospect i ve volumetric analysis of extent of resection ( EOR ) was carried out to assess surgical outcomes in adults diagnosed with hemispheric low grade gliomas ( LGGs ) . MATERIAL S AND METHODS 68 consecutive patients diagnosed with LGGs were enrolled in the study .  Pre- and post-operative tumor volumes and EOR were measured based on FLAIR MRI . Dynamic susceptibility contrast perfusion magnetic resonance imaging ( DSC MRI ) was used for the assessment of relative cerebral blood volume ( rCBV ) . Three outcome measures were assessed : overall survival ( OS ) , progression-free survival ( PFS ) , and malignant degeneration-free survival ( MFS ) . RESULTS In 6 ( 9 % ) patients permanent neurologic deficits were observed . No statistically significant dependence between the EOR and the occurrence of permanent deficits was found . The eloquent or close to the eloquent location was statistically connected with lower EOR ( p=0.023 ) . The preoperative volume of tumors treated with gross total resection was significantly smaller than the volume of tumors in subtotal or partial resection groups ( p=0.020 , p<0.001 , respectively ) . OS was predicted by age at diagnosis ( p=0.032 ) , and rCBV ( p=0.002 ) . Progression and malignant transformation occurred in 22 ( 32 % ) and 11 ( 16 % ) out of 68 patients . PFS was predicted by preoperative tumor volume ( p=0.005 ) , postoperative tumor volume ( p=0.008 ) , the EOR ( p=0.001 ) , and by the rCBV ( p=0.033 ) . MFS was predicted by preoperative tumor volume ( p=0.0 
    Output:
    
Some retrospective studies and non-r and omized prospect i ve studies do seem to suggest improved OS and seizure control correlating to higher extent of resection .
Future research could focus on RCTs to determine outcomes benefits for biopsy versus resection