***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 
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    Input: CONTEXT Current and former smokers are currently being screened for lung cancer with computed tomography ( CT ) , although there are limited data on the effect screening has on lung cancer outcomes . R and omized controlled trials assessing CT screening are currently under way . OBJECTIVE To assess whether screening may increase the frequency of lung cancer diagnosis and lung cancer resection or may reduce the risk of a diagnosis of advanced lung cancer or death from lung cancer . DESIGN , SETTING , AND PARTICIPANTS Longitudinal analysis of 3246 asymptomatic current or former smokers screened for lung cancer beginning in 1998 either at 1 of 2 academic medical centers in the United States or an academic medical center in Italy with follow-up for a median of 3.9 years . INTERVENTION Annual CT scans with comprehensive evaluation and treatment of detected nodules . MAIN OUTCOME MEASURES Comparison of predicted with observed number of new lung cancer cases , lung cancer resections , advanced lung cancer cases , and deaths from lung cancer . RESULTS There were 144 individuals diagnosed with lung cancer compared with 44.5 expected cases ( relative risk [ RR ] , 3.2 ; 95 % confidence interval [ CI ] , 2.7 - 3.8 ; P<.001 ) . There were 109 individuals who had a lung resection compared with 10.9 expected cases ( RR , 10.0 ; 95 % CI , 8.2 - 11.9 ; P<.001 ) . There was no evidence of a decline in the number of diagnoses of advanced lung cancers ( 42 individuals compared with 33.4 expected cases ) or deaths from lung cancer ( 38 deaths due to lung cancer observed and 38.8 expected ; RR , 1.0 ; 95 % CI , 0.7 - 1.3 ; P = .90 ) . CONCLUSIONS Screening for lung cancer with low-dose CT may increase the rate of lung cancer diagnosis and treatment , but may not meaningfully reduce the risk of advanced lung cancer or death from lung cancer . Until more conclusive data are available , asymptomatic individuals should not be screened outside of clinical research studies that have a reasonable likelihood of further clarifying the potential benefits and risks From 2002–2004 , the Lung Screening Study  ( LSS ) of the National Lung Screening Trial ( NLST ) enrolled 34,614 participants , aged 55–74 years , at increased risk for lung cancer due to heavy cigarette smoking . Participants , r and omized to st and ard chest X-ray ( CXR ) or computed tomography ( CT ) arms at ten screening centers , received up to three imaging screens for lung cancer at annual intervals . Participant medical histories and radiologist-interpreted screening results were transmitted to the LSS coordinating center , while all images were retained at local screening centers . From 2005–2007 , all CT exams were uniformly de-identified and delivered to a central repository , the CT Image Library ( CTIL ) , on external hard drives ( 94 % ) or CD/DVD ( 5.9 % ) , or over a secure Internet connection ( 0.1 % ) . Of 48,723 CT screens performed , only 176 ( 0.3 % ) were unavailable ( lost , corrupted , compressed ) while 48,547 ( 99.7 % ) were delivered to the CTIL . Described here is the experience organizing , implementing , and adapting the clinical -trial workflow surrounding the image retrieval , de- identification , delivery , and archiving of available  LSS – NLST CT exams  for the CTIL , together with the quality assurance procedures associated with those collection tasks . This collection of CT exams , obtained in a specific , well-defined participant population under a common protocol at evenly spaced intervals , and its attending demographic and clinical information , are now available to lung-disease investigators and developers of computer-aided-diagnosis algorithms . The approach to large scale , multi-center trial CT image collection detailed here may serve as a useful model , while the experience reported should be valuable in the planning and execution of future equivalent endeavors PURPOSE To prospect ively evaluate the utility of whole-body cancer screening with multiple modalities including [(18)F]fluorodeoxyglucose positron emission tomography ( FDG-PET ) in a healthy population . This report summarizes the results of the first three annual screenings . PARTICIPANTS AND METHODS A total of 1,197 healthy volunteers > or = 35 years old were enrolled between August 2003 and July 2004 and offered annual cancer screening for 5 years with subsequent long-term follow-up . Screening modalities included were whole-body FDG-PET , chest and abdominal computed tomography ( CT ) , brain and pelvic magnetic resonance imaging , several tumor markers , and fecal occult blood testing . RESULTS As of the end of 2006 , 22 primary cancers were pathologically confirmed . Nineteen of 22 were detected by the screening ; 18 in the initial , one in the second , and none in the third . Three were diagnosed after development of symptoms . Of the 18 detected in the initial screening ( six thyroid , four lung , three prostate , three breast , one endometrial , and one thymic ) , 12 were at stage I and 11 were PET positive . PET-negative cancers were detected by CT or the prostate-specific antigen ( PSA ) test . Sensitivity and specificity were 50.0 % ( 11 of 22 ) and 93.2 % ( 1,095 of 1,175 ) , respectively , for FDG-PET alone and 81.8 % ( 18 of 22 ) and 82.0 % ( 963 of 1,175 ) , respectively , for the combination of imaging modalities and PSA . CONCLUSION While FDG-PET alone is insufficient , whole-body cancer screening with selected modalities including FDG-PET has initial performance supporting possible utility by detecting a wide variety of early-stage cancers with reasonable sensitivity . However , the detection of many indolent cancers and false positives necessitate continuing study for appropriate evaluation PURPOSE To report results of a 5-year prospect i ve low-dose helical chest computed tomographic ( CT ) study of a cohort at high risk for lung cancer . MATERIAL S AND METHODS After informed written consent was obtained , 1520 individuals were enrolled . Protocol was approved by institutional review board and National Cancer Institute and was compliant with Health Insurance Portability and Accountability Act , or HIPAA . Participants were aged 50 years and older and had smoked for more than 20 pack-years . Participants underwent five annual ( one initial and four subsequent ) CT examinations . A significant downward shift was evaluated in non-small cell lung cancers detected initially from advanced stage down to stage I by using a one-sided binomial test of proportions . Poisson regression and Fisher exact tests were used for comparisons with Mayo Lung Project . RESULTS In 788 ( 52 % ) men and 732 ( 48 % ) women , 61 % ( 927 of 1520 ) were current smokers , and 39 % were former smokers . After five annual CT examinations , 3356 uncalcified lung nodules were identified in 1118 ( 74 % ) participants . Sixty-eight lung cancers were diagnosed ( 31 initial , 34 subsequent , three interval cancers ) in 66 participants . Twenty-eight subsequent cases of non-small cell cancers were detected , of which 17 ( 61 % ; 95 % confidence interval : 41 % , 79 % ) were stage I tumors . Diameter of cancers detected subsequently was 5 - 50 mm ( mean , 14.4 mm ; median , 10.0 mm ) . Analysis for a more than 50 % shift in proportion of stage I non-small cell cancer detection did not show statistical significance . Forty-eight participants died of various causes since enrollment . Lung cancer mortality rate for incidence portion of trial was 1.6 per 1000 person-years . There was no significant difference in lung cancer mortality rates of cancers detected in subsequent examinations between this trial and Mayo Lung Project after separation of participants into subsets ( 2.8 vs 2.0 per 1000 person-years , P = .43 ) . CONCLUSION CT allows detection of early-stage lung cancers . Benign nodule detection rate is high . Results suggest no stage shift BACKGROUND Lung cancer has the highest mortality-rate per cancer , with an overall 5-year survival < 15 % . Several non-r and omized studies pointed out the high sensitivity of low dose computed tomography ( LDCT ) to detect early stage lung cancer . In France , Depiscan , a pilot RCT of LDCT versus chest X-ray ( CXR ) , started on October 2002 to determine the feasibility of enrollment by general practitioners ( GPs ) , investigations and diagnostic procedures by university hospital radiologists and multidisciplinary teams , data management by central ized clinical research assistants , and anticipate the future management of a large national trial . METHODS GPs and occupational physicians ( OPs ) selected and enrolled 1000 subjects in 1 year . Eligible subjects were asymptomatic males or females aged 50 - 75 years with a current or former cigarette smoking history of > /=15 cigarettes per day for at least 20 years ( former smokers having quit < 15 years prior to enrollment ) . Based to r and omization , annual LDCT or CXR screenings were planned at baseline and annually for 2 years . RESULTS Between October 2002 and December 2004 , 765 subjects were enrolled by 89 out of the 232 participating GPs and OPs . Complete clinical and imaging baseline data were available for 621 individuals out of the 765 enrolled , due to 144 noncompliant subjects who withdrew their consent . At least one nodule was detected in 152 out of 336 subjects ( 45.2 % ) in the LDCT screening , versus 21 out of 285 subjects ( 7.4 % ) in the CXR screening arm . Eight lung cancers were detected in the LDCT arm and one in the CXR arm . DISCUSSION This pilot trial allows estimating that non-calcified nodules are 10 [ 6.36 - 17.07 ] times more often detected from LDCT than from CXR . However enrollment by GPs was more difficult than expected with 41 % active investigators and a high rate ( 19 % ) of noncompliant patients . This experience speaks to the need for a high level of GPs formation and a large , coordinated clinical research team in such a trial . TRIAL REGISTRATION NUMBER 02526 BACKGROUND A troubling aspect of cancer screening is the potential for overdiagnosis , i.e. , detection of disease that , in the absence of screening , would never have been diagnosed . Overdiagnosis is of particular concern in lung cancer screening because newer screening modalities can identify small nodules of unknown clinical significance . Previously published analyses of data from the Mayo Lung Project , a large r and omized controlled trial conducted among 9211 male cigarette smokers in the 1970s and early 1980s indicated that overdiagnosis might exist in lung cancer screening . At the end of follow-up ( July 1 , 1983 ) , no difference in lung cancer mortality was observed , but an excess of 46 cases in the intervention arm suggested overdiagnosis . Because that excess could instead have result ed from short follow-up time , we investigated this possibility by conducting long-term lung cancer incidence follow-up . METHODS We investigated the lung cancer status through 1999 of the 7118 participants in the Mayo Lung Project who were alive and without diagnosed lung cancer in 1983 by use of medical records , surveys mailed to participants or next-of-kin , and state death certificates . RESULTS Information was available for 6101 participants , including 811 with inconclusive lung cancer status . From November 1971 through December 31 , 1999 , 585 participants in the intervention arm and 500 in the usual-care arm were diagnosed with lung cancer . CONCLUSIONS The persistence of excess cases in the intervention arm after 16 additional years of follow-up provides continued support for overdiagnosis in lung cancer screening A prospect i ve study design ed to detect early lung cancer in a high risk outpatient volunteer population is in progress . At present all 10,362 volunteers have been recruited into the project . A review of the radiographs of patients with lung cancer identified on the initial screen , or in retrospect , has led to the following conclusions : ( 1 ) Independent double reading is important in a screening project . ( 2 ) There are no reliable radiographic criteria to distinguish early lung cancer from benign disease . ( 3 ) The lateral chest radiograph is useful in the high risk patient . From these conclusions the authors have three recommendations for the practicing radiologist . ( 1 ) Since double reading improves sensitivity , attempt to doubly read a chest radiograph by removing your eyes from the film and look at it a second time before finalizing your report . ( 2 ) Consider any newly appearing , noncalcified lesion in the chest radiograph of a high risk individual as primary lung cancer until proven otherwise . ( 3 ) Consider the " routine chest radiograph " in a high risk patient as a challenge to detect early lung cancer rather than the drudgery of day to day clinical practice Cigarette‐smoking males ( 6,364 ) , aged 40–64 , were r and omized into an intervention group which received 6‐monthly screening by chest X‐ray and sputum cytology , and a control group which received no asymptomatic investigation . After 3 years , both groups entered a follow‐up period during which they received annual chest X‐rays . Lung cancer cases detected by screening were identified 
    Output:
    
The baseline data from six r and omized controlled trials offer no compelling data in favor or against the use of LDCT screening for lung cancer .