***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: Background The effects of low-dose CT screening on disease stage shift , mortality and overdiagnosis are unclear . Lung cancer findings and mortality rates are reported at the end of screening in the Danish Lung Cancer Screening Trial . Methods 4104 men and women , healthy heavy smokers/former smokers were r and omised to five annual low-dose CT screenings or no screening . Two experienced chest radiologists read all CT scans and registered the location , size and morphology of nodules . Nodules between 5 and 15 mm without benign characteristics were rescanned after 3 months . Growing nodules ( > 25 % volume increase and /or volume doubling time<400 days ) and nodules > 15 mm were referred for diagnostic workup . In the control group , lung cancers were diagnosed and treated outside the study by the usual clinical practice . Results Participation rates were high in both groups ( screening : 95.5 % ; control : 93.0 % ; p<0.001 ) . Lung cancer detection rate was 0.83 % at baseline and mean annual detection rate was 0.67 % at incidence rounds ( p=0.535 ) . More lung cancers were diagnosed in the screening group ( 69 vs 24 , p<0.001 ) , and more were low stage ( 48 vs 21 stage I – IIB non-small cell lung cancer ( NSCLC ) and limited stage small cell lung cancer ( SCLC ) , p=0.002 ) , whereas frequencies of high-stage lung cancer were the same ( 21 vs 16 stage IIIA – IV NSCLC and extensive stage SCLC , p=0.509 ) . At the end of screening , 61 patients died in the screening group and 42 in the control group ( p=0.059 ) . 15 and 11 died of lung cancer , respectively ( p=0.428 ) . Conclusion CT screening for lung cancer brings forward early disease , and at this point no stage shift or reduction in mortality was observed . More lung cancers were diagnosed in the screening group , indicating some degree of overdiagnosis and need for longer follow-up BACKGROUND Results of r and omized clinical trials ( RCTs ) are needed to assess the efficacy of lung cancer screening with low-dose chest computed tomography ( CT ) in reducing lung cancer mortality . We report design and results of enrolment and baseline screening test in the ITALUNG trial , a RCT . METHODS Invitation letters were sent to subjects of 55 - 69 years of age clients of 269 general practitioners . Smokers or former smokers of at least 20 pack/years were eligible and after written consent were r and omized in an active arm undergoing a low-dose CT annually for 4 years and in a control arm receiving no screening . Management of positive screening test was carried out using follow-up low-dose CT , fluorodeoxyglucose positron emission tomography , fine needle aspiration cytology and fiber optic bronchoscopy . RESULTS A sample of 3206 eligible subjects was achieved by sending 71,232 letters ( enrolment efficacy = 4.5 % ) . Subjects in control ( n = 1593 ) and active ( n = 1613 ) arm were balanced for age , gender and smoking history . Two-hundred and seven ( 12.8 % ) subjects did not undergo CT after r and omization . The baseline screening test was positive in 426 ( 30.3 % ) of 1406 subjects . Twenty-one lung cancers ( prevalence = 1.5 % ) were found in 20 subjects : 18 non-small cell lung cancer ( NSCLC ) , 2 small cell lung cancer ( SCLC ) and a case of typical carcinoid . Ten NSCLC ( 47.6 % ) were in Stage I. Sixteen fine needle aspirations were performed in 15 lung cancers , with a positive result in 12 ( 75 % ) cases . One biopsy only ( 6.3 % ) was performed on a benign lesion . Seventeen lung cancers ( 81 % ) were treated with surgical resection in 16 subjects . One subject underwent surgery for a benign lesion ( 5.5 % of all surgical resections ) . CONCLUSIONS Recruitment by mail of high risk subjects for a lung cancer screening RCT is feasible but not efficient . Results of the baseline screening test in the active arm of the ITALUNG trial are substantially in line with those of RCT and observational studies Results are reported of a prospect i ve study , carried out by the  Mass Radiography Service of the North-West Metropolitan Region for the purpose of evaluating early lung cancer detection by six-monthly chest radiographs . The lung cancer experience of a test group of 29,723 men aged 40 and over who were offered six-monthly chest radiographs over a period of three years is compared with a similarly constituted control group of 25,311 men who were radiographed only at the beginning and the end of the study . In the test group 29,416 men ( 98·9 % ) and in the control group 25,044 men ( 99 % ) were followed up . The methods employed to achieve this result are analysed . The six-monthly surveys of the test group yielded 65 cases of lung cancer , giving an annual incidence and detection rate of 0·9 per thous and examined . Of these cases 65 % were resected . Of all cases of lung cancer in the test group , irrespective of their source of detection , 43·6 % were operable , compared with 29 % in the control group . The difference ( P=0·03 ) is statistically significant . The annual mortality rate from lung cancer based on 62 deaths in the test group and 59 deaths in the control was 0·7 and 0·8 per thous and respectively . The conclusions are reached that since early detection by six-monthly chest radiographs has not significantly reduced the mortality from lung cancer in a population at risk , a policy of such large-scale surveys of men in the cancer age would not seem justified , but that the increased discovery of resectable lung cancer by this method forms a reasonable basis for encouraging individuals in high-risk groups to make regular use of existing mass radiography facilities Two r and omized controlled trials of lung cancer screening initiated in the 1970s , the Johns Hopkins Lung Project and the Memorial Sloan‐Kettering Lung Study , compared 1 arm that received annual chest X‐ray and 4‐monthly sputum cytology ( dual‐screen ) to a second arm that received annual chest X‐ray only . Previous publications from these trials reported similar lung cancer mortality between the 2 groups . However , these findings were based on incomplete follow‐up , and each trial on its own was underpowered to detect a modest mortality benefit The aim of this study was analysis of incidence results in a prospect i ve one-arm feasibility study of lung cancer screening with low-radiation-dose spiral computed tomography in heavy smokers . Eight hundred seventeen smokers ( ≥40 years , ≥20 pack years of smoking history ) underwent baseline low-dose CT . Biopsy was recommended in nodules > 10 mm with CT morphology suggesting malignancy . In all other lesions follow-up with low-dose CT was recommended . Annual repeat CT was offered to all study participants . Six hundred sixty-eight ( 81.8 % ) of the 817 subjects underwent annual repeat CT  with a total of 1735 follow-up years . Follow-up of non-calcified nodules present at baseline CT demonstrated growth in 11 of 792 subjects . Biopsy was performed in 8 of 11 growing nodules 7 of which represented lung cancer . Of 174 new nodules , 3 represented lung cancer . The 10 screen-detected lung cancers were all non-small cell cancer ( 6 stage IA , 1 stage IB , 1 stage IIIA , 2 stage IV ) . Five symptom-diagnosed cancers ( 2 small cell lung cancer : 1 limited disease , 1 extensive disease , 3 central /endobronchial non-small cell lung cancer , 2 stage IIIA , 1 stage IIIB ) were diagnosed because of symptoms in the 12-month interval between two annual CT scans . Incidence of lung cancer was lower than prevalence , screen-detected cancers were smaller , and stage I was found in 70 % ( 7 of 10 ) of screen-detected tumors . Only 27 % ( 4 of 15 ) of invasive procedures was performed for benign lesions ; however , 33 % ( 5 of 15 ) of all cancers diagnosed in the population were symptom-diagnosed cancers ( 3 central NSCLC , all stage III , 2 SCLC ) demonstrating the limitations of CT screening The Memorial Sloan-Kettering lung cancer screening program was begun in 1974 to evaluate sputum cytology as a supplement to the annual chest x-ray examination for early detection and diagnosis . The 10,040 adult , male cigarette smokers who enrolled were r and omly assigned to receive annual chest x-ray examinations only or a dual screen with annual chest x-ray examination and four monthly sputum cytology evaluation . Over 40 percent of the 288 who developed lung cancer were diagnosed in stage I , and their survival was 76 percent at five years ; overall survival was 35 percent . Nearly one third of the lung cancers detected on first examination on the dual screen , and 14 percent of those on subsequent examinations were found by cytologic examination . The same number of cancers developed in the x-ray screen only group , and were diagnosed at a later date . Despite the delay , survival and mortality were the same , suggesting that the squamous carcinomas detected by cytologic examination alone are very slow growing and tend to remain localized until detectable by x-ray examination BACKGROUND Low-dose spiral CT of the chest effectively detects early-stage  lung cancer in high-risk individuals . The high rate of benign nodules and issues of making a differential diagnosis are critical factors that currently hamper introduction of large-scale screening programmes . We investigated the efficacy of repeated yearly spiral CT and selective use of positron emission tomography ( PET ) in a large cohort of high-risk volunteers . METHODS We enrolled 1035 individuals aged 50 years or older who had smoked for 20 pack-years or more . All patients underwent annual low-dose CT , with or without PET , for 5 years . Lesions up to 5 mm were deemed non-suspicious and low-dose CT was repeated after 12 months ( year 2 ) . FINDINGS By year 2 , 22 cases of lung cancer had been diagnosed ( 11 at baseline , 11 at year 2 ) . 440 lung lesions were identified in 298 ( 29 % ) participants , and 95 were recalled for high-resolution contrast CT . PET scans were positive in 18 of 20 of the identified cancer cases . Six patients underwent surgical biopsy for benign disease because of false-positive results ( 6 % of recalls , 22 % of invasive procedures ) . Complete resection was achieved in 21 ( 95 % ) lung cancers , 17 ( 77 % ) were pathological stage I ( 100 % at year 2 ) , and the mean tumour size was 18 mm . There were no interval lung cancers in the 2.5 years of follow-up ( average time on study from r and omisation to last contact ) , although 19 individuals were diagnosed with another form of cancer ( two deaths and 17 non-fatal admissions ) . INTERPRETATION Combined use of low-dose spiral CT and selective PET effectively detects early lung cancer . Lesions up to 5 mm can be checked again at 12 months without major risks of progression BACKGROUND Reliable risk prediction tools for estimating individual probability of lung cancer have important public health implication s. We constructed and vali date d a comprehensive clinical tool for lung cancer risk prediction by smoking status . METHODS Epidemiologic data from 1851 lung cancer patients and 2001 matched control subjects were r and omly divided into separate training ( 75 % of the data ) and validation ( 25 % of the data ) sets for never , former , and current smokers , and multivariable models were constructed from the training sets . The discriminatory ability of the models was assessed in the validation sets by examining the areas under the receiver operating characteristic curves and with concordance statistics . Absolute 1-year risks of lung cancer were computed using national incidence and mortality data . An ordinal risk index was constructed for each smoking status category by summing the odds ratios from the multivariable regression analyses for each risk factor . RESULTS All variables that had a statistically significant association with lung cancer ( environmental tobacco smoke , family history of cancer , dust exposure , prior respiratory disease , and smoking history variables ) have strong biologically plausible etiologic roles in the disease . The concordance statistics in the validation sets for the never , former , and current smoker models were 0.57 , 0.63 , and 0.58 , respectively . The computed 1-year absolute risk of lung cancer for a hypothetical male current smoker with an estimated relative risk close to 9 was 8.68 % . The ordinal risk index performed well in that true-positive rates in the design ated high-risk categories were 69 % and 70 % for current and former smokers , respectively . CONCLUSIONS If confirmed in other studies , this risk assessment procedure could use easily obtained clinical information to identify individuals who may benefit from increased screening surveillance for lung cancer . Although the concordance statistics were modest , they are consistent with those from other risk prediction models 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 
    Output:
    
RESULTS Several large r and omized controlled trials ( RCTs ) , including a recent one , have demonstrated that screening for lung cancer using a chest radiograph does not reduce the number of deaths from lung cancer .
Screening is a complex interplay of selection ( a population with sufficient risk and few serious comorbidities ) , the value of the screening test , the interval between screening tests , the availability of effective treatment , the risk of complications or harms as a result of screening , and the degree with which the screened individuals comply with screening and treatment recommendations .
Screening with LDCT of appropriate individuals in the context of a structured process is associated with a significant reduction in the number of lung cancer deaths in the screened population .