***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: Prognosis studies are investigations of future events or the evaluation of associations between risk factors and health outcomes in population s of patients ( 1 ) . The results of such studies improve our underst and ing of the clinical course of a disease and assist clinicians in making informed decisions about how best to manage patients . Prognostic research also informs the design of intervention studies by helping define subgroups of patients who may benefit from a new treatment and by providing necessary information about the natural history of a disorder ( 2 ) . There has recently been a rapid increase in the use of systematic review methods to synthesize the evidence on research questions related to prognosis . It is essential that investigators conducting systematic review s thoroughly appraise the method ologic quality of included studies to be confident that a study 's design , conduct , analysis , and interpretation have adequately reduced the opportunity for bias ( 3 , 4 ) . Caution is warranted , however , because inclusion of method ologically weak studies can threaten the internal validity of a systematic review ( 4 ) . This follows abundant empirical evidence that inadequate attention to biases can cause invalid results and inferences ( 5 - 9 ) . However , there is limited consensus on how to appraise the quality of prognosis studies ( 1 ) . A useful framework to assess bias in such studies follows the basic principles of epidemiologic research ( 10 , 11 ) . We focus on 6 areas of potential bias : study participation , study attrition , prognostic factor measurement , confounding measurement and account , outcome measurement , and analysis . The main objectives of our review of review s are to describe methods used to assess the quality of prognosis studies and to describe how well current practice s assess potential biases . Our secondary objective is to develop recommendations to guide future quality appraisal , both within single studies of prognostic factors and within systematic review s of the evidence . We hope this work facilitates future discussion and research on biases in prognosis studies and systematic review s. Methods Literature Search and Study Selection We identified systematic review s of prognosis studies by search ing MEDLINE ( 1966 to October 2005 ) using the search strategy recommended by McKibbon and colleagues ( 12 ) . This strategy combines broad search terms for systematic review s ( systematic review .mp ; meta- analysis .mp ) and a sensitive search strategy for prognosis studies ( cohort , incidence , mortality , follow-up studies , prognos * , predict * , or course ) . We also search ed the reference lists of included review s and method ologic papers to identify other relevant publications . We restricted our search to English- language publications . One review er conducted the search and selected the studies . Systematic review s , defined as review s of published studies with a comprehensive search and systematic selection , were included if they assessed the method ologic quality of the included studies by using 1 or more explicit criteria . We excluded studies if they were meta-analyses of independent patient data only , if their primary goal was to investigate the effectiveness of an intervention or specific diagnostic or screening tests , or if they included studies that were not done on humans . Data Extraction and Synthesis Individual items included in the quality assessment of the systematic review s were recorded as they were reported in the publication ( that is , the information that would be available to readers and future review ers ) . We review ed journal Web sites and contacted the authors of the systematic review s for additional information when authors made such an offer in their original papers . When review s assessed different study design s by using different sets of quality items , we extracted only those items used to assess cohort studies . We constructed a comprehensive list of distinct items that the review s used to assess the quality of their included studies . The full text of each review was screened . All items used by the review authors to assess the quality of studies were extracted into a computerized spreadsheet by 1 review er . Two experienced review ers , a clinical epidemiologist and an epidemiologist , independently synthesized the quality items extracted from the prognosis review s to determine how well the systematic review s assessed potential biases . We did this in 3 steps : 1 ) identified distinct concepts or domains addressed by the quality items ; 2 ) grouped each extracted quality item into the appropriate domain or domains ; and 3 ) identified the domains necessary to assess potential biases in prognosis studies . We then used this information to assess how well the review s ' quality assessment included items from the domains necessary to assess potential biases . After completing each of the first 3 steps , the review ers met to attempt to reach a consensus . The consensus process involved each review er presenting his or her observations and results , followed by discussion and debate . A third review er was available in cases of persistent disagreement or uncertainty . In the first step , all domains addressed by the quality items were identified . The first review er iteratively and progressively defined the domains as items were extracted from the included review s. The second review er defined domains from a r and om list of all extracted quality items . Limited guidance was provided to the review ers so that their assessment s and definitions of domains would be independent . The review ers agreed on a final set of domains that adequately and completely defined all of the extracted items . In the second step , review ers independently grouped each extracted item into the appropriate domains . Review ers considered each extracted item by asking , What is each particular quality item addressing ? or What are the review 's authors getting at with the particular quality assessment item ? . Items were grouped into the domain or domains that best represented the concepts being addressed . For example , the extracted items at least 80 % of the group originally identified was located for follow-up and follow-up was sufficiently complete or does n't jeopardize validity were each independently classified by both review ers as assessing the domain completeness of follow-up adequate , whereas the extracted item quantification and description of all subjects lost to follow-up was classified as assessing the domain completeness of follow-up described . In the third step , we identified the domains necessary to assess potential biases . Each review er considered the ability of the identified domains to adequately address , at least in part , 1 of the following 6 potential biases : 1 ) study participation , 2 ) study attrition , 3 ) prognostic factor measurement , 4 ) confounding measurement and account , 5 ) outcome measurement , and 6 ) analysis . Domains were considered to adequately address part of the framework if information garnered from that domain would inform the assessment of potential bias . For example , both review ers judged that the identified domain study population represents source population or population of interest assessed potential bias in a prognosis study , whereas the domain research question definition did not , although the latter is an important consideration in assessing the inclusion of studies in a systematic review . Finally , on the basis of our previous ratings , we looked at whether each review included items from the domains necessary to assess the 6 potential biases . We calculated the frequency of systematic review s by assessing each potential bias and the number of review s that adequately assessed bias overall . From this systematic synthesis , we developed recommendations for improving quality appraisal in future systematic review s of prognosis studies . We used Microsoft Access and Excel 2002 ( Microsoft Corp. , Redmond , Washington ) for data management and SAS for Windows , version 9.1 ( SAS Institute , Inc. , Cary , North Carolina ) for descriptive statistics . Role of the Funding Sources The funding sources , the Canadian Institutes of Health Research , the Canadian Chiropractic Research Foundation , the Ontario Chiropractic Association , and the Ontario Ministry of Health and Long Term Care , did not have a role in the collection , analysis , or interpretation of the data or in the decision to su bmi t the manuscript for publication . Results We identified 1384 potentially relevant articles . Figure 1 shows a flow chart of studies that were included and excluded . Figure 2 shows the number of review s identified by year of publication . We excluded 131 systematic review s of prognosis studies that did not seem to include any quality assessment of the included studies ; this represented 44 % of prognosis review s. We included 163 review s of prognosis studies in our analysis ( 13 - 175 ) . The most common topics were cancer ( 15 % ) , musculoskeletal disorders and rheumatology ( 13 % ) , cardiovascular ( 10 % ) , neurology ( 10 % ) , and obstetrics ( 10 % ) . Other review s included a wide range of health and health care topics . Sixty-three percent of the review s investigated the association between a specific prognostic factor and a particular outcome ; the remainder investigated multiple prognostic factors or models . The number of primary studies included in each systematic review ranged from 3 to 167 ( median , 18 [ interquartile range , 12 to 31 ] ) . A complete description of the included review s is available from the authors on request . Figure 1 . Flow diagram of inclusion and exclusion criteria of systematic review s. Figure 2 . Number of systematic review s of prognosis studies identified over time . Quality Items One hundred fifty-three review s provided adequate detail to allow extraction of quality items . Eight hundred eighty-two distinct quality items were extracted from the review s. Most review s developed their own set of quality items , with only a few applying criteria from previous review s. Most quality items BACKGROUND Phase 1 and 2 clinical trials of the BRAF kinase inhibitor vemurafenib ( PLX4032 ) have shown response rates of more than 50 % in patients with metastatic melanoma with the BRAF V600E mutation . METHODS We conducted a phase 3 r and omized clinical trial comparing vemurafenib with dacarbazine in 675 patients with previously untreated , metastatic melanoma with the BRAF V600E mutation . Patients were r and omly assigned to receive either vemurafenib ( 960 mg orally twice daily ) or dacarbazine ( 1000 mg per square meter of body-surface area intravenously every 3 weeks ) . Co primary end points were rates of overall and progression-free survival . Secondary end points included the response rate , response duration , and safety . A final analysis was planned after 196 deaths and an interim analysis after 98 deaths . RESULTS At 6 months , overall survival was 84 % ( 95 % confidence interval [ CI ] , 78 to 89 ) in the vemurafenib group and 64 % ( 95 % CI , 56 to 73 ) in the dacarbazine group . In the interim analysis for overall survival and final analysis for progression-free survival , vemurafenib was associated with a relative reduction of 63 % in the risk of death and of 74 % in the risk of either death or disease progression , as compared with dacarbazine ( P<0.001 for both comparisons ) . After review of the interim analysis by an independent data and safety monitoring board , crossover from dacarbazine to vemurafenib was recommended . Response rates were 48 % for vemurafenib and 5 % for dacarbazine . Common adverse events associated with vemurafenib were arthralgia , rash , fatigue , alopecia , keratoacanthoma or squamous-cell carcinoma , photosensitivity , nausea , and diarrhea ; 38 % of patients required dose modification because of toxic effects . CONCLUSIONS Vemurafenib produced improved rates of overall and progression-free survival in patients with previously untreated melanoma with the BRAF V600E mutation . ( Funded by Hoffmann-La Roche ; BRIM-3 Clinical Trials.gov number , NCT01006980 . ) BACKGROUND / AIM Recent progress with BRAF and immune checkpoint inhibitors has dramatically changed the treatment l and scape of metastatic melanoma ( MM ) . The limited duration of responses to new agents , however , justifies the , still important , role of chemotherapy in the management of MM . This study prospect ively explored biomarkers to first-line temozolomide-based chemotherapy . MATERIAL S AND METHODS Tumor sample s from patients with advanced MM who received first-line therapy with the PVT combination ( cisplatin-vinblastine-temozolomide ) , i.e. cisplatin ( CDDP ) 30 mg/m2 ( days 1 - 3 ) i.v . , vinblastine ( CVT ) 2 mg/m2 ( days 1 - 3 ) i.v . , temozolomide ( TMZ ) 150 mg/m2 ( days 1 - 5 ) orally , every 21 days , were collected . Biomarkers ( MGMT , ERCC1 , p16 ) , were evaluated by immunohistochemistry and BRAF mutations by PCR/sequencing . RESULTS Out of 35 patients included in this clinical phase II study , 12 objective response rates were achieved ( ORR ; 34 % ) including 1 complete response CR ; 9 disease stabilisations ( SD ; 26 % ) , with overall clinical benefit rate ( CR+PR+SD ) 60 % , median response duration 6 months ( 95 % confidence interval (CI)=2 - 16 ) , median PFS 4 months ( 95 % CI=2 - 6 ) , median OS 12 months ( 95 % CI=6 - 25 ) and 1-year survival rate 52 % . From 24 tumor sample s evaluated for biomarkers , 13 ( 54 % ) were BRAF mutated and 11 ( 46 % ) wild-type ( wt ) . Patients with BRAF-mutated tumors showed better response rates compared to BRAF wild-type ( 39 % vs. 27 % ) and improved PFS/OS . Sub-analyses , according to BRAF status , did not reveal any significant correlations with excision repair cross-complementation group 1 enzyme ( ERCC1 ) , however , in patients with BRAF-mutated tumors , low O6-methylguanine-DNA methyltransferase ( MGMT ) nuclear expression correlated with better PFS , p=0.0384 . CONCLUSION First-line PVT chemotherapy for MM is efficacious and well-tolerated . Interesting ' hypothesis-generating ' results show that c and i date predictive biomarkers could identify subgroups of patients , i.e. tumors with BRAF mutation and low MGMT expression , with better outcomes following TMZ-based chemotherapy , thus warranting further evaluation in larger cohorts BACKGROUND Activating mutations in serine 
    Output:
    
Conclusion : Although there was substantial heterogeneity between the studies , the overall results demonstrated a poorer prognosis and OS in patients harbouring BRAF mutations .