***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: Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more The European Society of Thoracic Surgeons ( ESTS ) organized a workshop dealing with lymph node staging in non-small cell lung cancer . The objective of this workshop was to develop guidelines for definitions and the surgical procedures of intraoperative lymph node staging , and the pathologic evaluation of resected lymph nodes in patients with non-small cell lung cancer ( NSCLC ) . Relevant peer- review ed publications on the subjects , the experience of the participants , and the opinion of the ESTS members contributing on line , were used to reach a consensus . Systematic nodal dissection is recommended in all cases to ensure complete resection . Lobe-specific systematic nodal dissection is acceptable for peripheral squamous T1 tumors , if hilar and interlobar nodes are negative on frozen section studies ; it implies removal of , at least , three hilar and interlobar nodes and three mediastinal nodes from three stations in which the subcarinal is always included . Selected lymph node biopsies and sampling are justified to prove nodal involvement when resection is not possible . Pathologic evaluation includes all lymph nodes resected separately and those remaining in the lung specimen . Sections are done at the site of gross abnormalities . If macroscopic inspection does not detect any abnormal site , 2-mm slices of the nodes in the longitudinal plane are recommended . Routine search for micrometastases or isolated tumor cells in hematoxylin-eosin negative nodes would be desirable . R and omized controlled trials to evaluate adjuvant therapies for patients with these conditions are recommended . The adherence to these guidelines will st and ardize the intraoperative lymph node staging and pathologic evaluation , and improve pathologic staging , which will help decide on the best adjuvant therapy Summary Background The diagnosis and staging of lung cancer is an important process that identifies treatment options and guides disease prognosis . We aim ed to assess endobronchial ultrasound-guided transbronchial needle aspiration as an initial investigation technique for patients with suspected lung cancer . Methods In this open-label , multicentre , pragmatic , r and omised controlled trial , we recruited patients who had undergone a CT scan and had suspected stage I to IIIA lung cancer , from six UK centres and r and omly assigned them to either endobronchial ultrasound-guided transbronchial needle aspiration ( EBUS-TBNA ) or conventional diagnosis and staging ( CDS ) , for further investigation and staging . If a target node could not be accessed by EBUS-TBNA , then endoscopic ultrasound-guided fine needle aspiration ( EUS-FNA ) was allowed as an alternative procedure . R and omisation was stratified according to the presence of mediastinal lymph nodes measuring 1 cm or more in the short axis and by recruiting centre . We used a telephone r and omisation method with permuted blocks of four generated by a computer . Because of the nature of the intervention , masking of participants and consenting investigators was not possible . The primary endpoint was the time-to-treatment decision after completion of the diagnostic and staging investigations and analysis was by intention-to-diagnose . This trial is registered with Clinical Trials.gov , number NCT00652769 . Findings Between June 10 , 2008 , and July 4 , 2011 , we r and omly allocated 133 patients to treatment : 66 to EBUS-TBNA and 67 to CDS ( one later withdrew consent ) . Two patients from the EBUS-TBNA group underwent EUS-FNA . The median time to treatment decision was shorter with EBUS-TBNA ( 14 days ; 95 % CI 14–15 ) than with CDS ( 29 days ; 23–35 ) result ing in a hazard ratio of 1·98 , ( 1·39–2·82 , p<0·0001 ) . One patient in each group had a pneumothorax from a CT-guided biopsy sample ; the patient from the CDS group needed intercostal drainage and was admitted to hospital . Interpretation Transbronchial needle aspiration guided by endobronchial ultrasound should be considered as the initial investigation for patients with suspected lung cancer , because it reduces the time to treatment decision compared with conventional diagnosis and staging techniques . Funding UK Medical Research Council BACKGROUND To compare surgical results , pathological staging , and survival between complete and minimal mediastinal lymph node dissection for non-small cell lung cancer ( NSCLC ) . METHODS A r and omized controlled trial was carried out in 202 patients who were assigned to undergo either skeletonized complete mediastinal lymph node dissection ( CLD ) or minimal mediastinal lymph node dissection ( MLD ) .  Clinical and pathological characteristics , surgical results , postoperative staging , and five-year survival were recorded for statistical analysis . RESULTS Significantly more stations of lymph nodes were harvested through CLD , than MLD ( 8.9 vs. 6.2 , P < 0.001 ) . There was no difference in major complications ( CLD 14.7 % vs. MLD 14.0 % , P = 0.884 ) or postoperative death ( CLD 2.1 % vs. MLD 1.9 % , P = 0.904 ) . No significant difference was detected in pathological staging between the two groups . The pN2 rates ( 27.1 % vs. 24.2 % ) , skip-mediastinal metastasis ( 9.3 % vs. 7.4 % ) , and multi-stational mediastinal involvement ( 15.0 % vs. 16.8 % ) were similar between MLD and CLD . However , CLD had significantly better five-year survival than MLD ( 55.7 % vs. 37.7 % , P = 0.005 ) , especially in patients with a tumor size > 3 cm , pleural invasion , pN1-N2 , stage II-III , adenocarcinoma , and low-differentiation carcinoma . Upon multivariate analysis , CLD , along with stage I and high-differentiation , were independent prognostic factors for better overall survival . CONCLUSIONS Complete and minimal mediastinal dissections have similar surgical risks and mediastinal staging effect in patients with NSCLC . Minimal dissection is enough for early stage high-differentiation tumors . For patients with stage II-III or low-differentiation carcinoma , skeletonized complete mediastinal dissection may improve survival compared with minimal dissection OBJECTIVES Nodal upstaging is a quality indicator for oncological thoracic surgery and is found in up to 25 % of patients with clinical stage I ( cStage-I ) non-small-cell lung cancer ( NSCLC ) . In large retrospective series , lower N1 upstaging was reported after video-assisted thoracic surgery ( VATS ) resections . We studied the impact of central primary tumour location on nodal upstaging in cStage-I NSCLC . METHODS Consecutive patients operated for cStage-I NSCLC were selected from a prospect ively managed surgical data base . Tumour location was classified as central if the lesion was visible during st and ard video bronchoscopy . A nodal station mapping was drawn for each patient based on final pathological examination . Univariable and additive multivariable binary logistic regression analyses were performed . RESULTS Between 2007 - 2014 , 334 patients underwent anatomical resection for cStage-I NSCLC , either by open thoracotomy ( n = 158 ) or by VATS ( n = 176 ; conversion rate 1.7 % ) . All patients underwent imaging with [(18)F]-fluorodeoxyglucose positron emission tomography and computer tomography . Invasive mediastinal staging was performed in 24.6 % of patients . There were more central tumours in the open group ( 24.1 % , n = 38 ) compared with the VATS group ( 4.5 % , n = 8) . There was no significant difference between the number ( mean ± st and ard deviation ) of nodal stations examined ( open 5 ± 1.9 vs VATS 5 ± 1.7 , P = 0.99 ) . Pathological nodal upstaging was found in 15.9 % ( n = 53 ) of cStage-I patients . Nodal pN1 and pN2 upstaging were 13.3 and 8.2 % , respectively , for the open group , and 6.3 and 4.5 % , respectively , for the VATS group . In 32.6 % ( n = 15/46 ) of patients with a central cStage-I tumour pN1 , upstaging was found . A binary logistic regression model ( including tumour location , technique , tumour size , gender and histology ) showed that only tumour location had a significant impact on pN1 upstaging [ peripheral versus central ; odds ratio ( OR ) 5.07 ( confidence interval , CI : 1.89 - 13.60 ) , P = 0.001 ] , while surgical technique had no significant impact [ VATS versus open ; OR 0.74 ( CI : 0.31 - 1.78 ) , P = 0.50 ] . CONCLUSIONS The number of lymph node stations examined during VATS resections is similar to open resections for cStage-I NSCLC . Almost one-third of the patients with a central cStage-I NSCLC were upstaged to pN1 . Tumour location was the only independent variable for pN1 upstaging in logistic regression analysis . It is a potential bias in retrospective studies and should therefore be accounted for when comparing different surgical resection techniques for cStage-I NSCLC We design ed a prospect i ve trial to determine the long-term prognosis of video-assisted thoracoscopic ( VATS ) lobectomy versus conventional lobectomy for patients with clinical stage IA ( T1N0M0 ) lung cancer . Between January 1993 and June 1994 , 100 consecutive patients with clinical stage IA non-small cell lung carcinoma underwent either conventional lobectomy through an open thoracotomy  ( open group ; n= 52 ) or VATS lobectomy  ( VATS group ; n= 48 ) . Lymph node dissections were performed in a similar manner in both groups . No significant differences were observed in the number of dissected lymph nodes between the 2 groups . Pathologic N1 and N2 disease was found in 3 and 1 patients , respectively , from the open group , and in 2 and 1 patients , respectively , from the VATS group . During the follow-up period , distant metastases and local or regional recurrences developed in 7 and 3 of the open group patients , respectively , and in 2 and 3 of the VATS group patients , respectively . Two and one of the open and VATS group patients developed second primary cancers , respectively . The overall survival rates 5 years after surgery were 85 % and 90 % in the open and VATS groups , respectively ( log-rank test , p= 0.74 ; generalized Wilcoxon test , p= 0.91 ) . VATS lobectomy with lymph node dissection achieved an excellent 5-year survival , similar to that achieved by the conventional approach BACKGROUND Little prospect i ve , multiinstitutional data exist regarding the morbidity and mortality after major pulmonary resections for lung cancer or whether a mediastinal lymph node dissection increases morbidity and mortality . METHODS Prospect ively collected 30-day postoperative data was analyzed from 1,111 patients undergoing pulmonary resection who were enrolled from July 1999 to February 2004 in a r and omized trial comparing lymph node sampling versus mediastinal lymph node dissection for early stage lung cancer . RESULTS Of the 1,111 patients r and omized , 1,023 were included in the analysis . Median age was 68 years ( range , 23 to 89 years ) ; 52 % were men . Lobectomy was performed in 766 ( 75 % ) and pneumonectomy in 42 ( 4 % ) . Pathologic stage was IA in 424 ( 42 % ) , IB in 418 ( 41 % ) , IIA in 37 ( 4 % ) , IIB in 97 ( 9 % ) , and III in 45 ( 5 % ) . Lymph node sampling was performed in 498 patients and lymph node dissection in 525 . Operative mortality was 2.0 % ( 10 of 498 ) for lymph node sampling and 0.76 % ( 4 of 525 ) for lymph node dissection . Complications occurred in 38 % of patients in each group . Lymph node dissection had a longer median operative time and greater total chest tube drainage ( 15 minutes , 121 mL , respectively ) . There was no difference in the median hospitalization , which was 6 days in each group ( p = 0.404 ) . CONCLUSIONS Complete mediastinal lymphadenectomy adds little morbidity to a pulmonary resection for lung cancer . These data from a current , multiinstitutional cohort of patients who underwent a major pulmonary resection constitute a new baseline with which to compare results in the future PURPOSE We conducted a r and omized trial to investigate whether systematic nodal dissection ( SND ) is superior to mediastinal lymph nodal sampling ( MLS ) in surgical treatment of non-small cell lung cancer ( NSCLC ) . METHODS The patients resectable clinical Stage I-IIIA NSCLC were r and omly assigned to lung resection combined with SND or lung resection combined with MLS . 
    Output:
    
The finding of clinical ly important surgically related morbidities but lower perioperative mortality with lymphadenectomy seems inconsistent .