***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: STUDY OBJECTIVE To evaluate the feasibility of lung cancer screening using low-dose spiral CT as a part of annual health examinations . DESIGN Nonr and omized , screening practice . METHODS From April 1998 to August 2000 , CT screening was performed as a part of annual health examinations on a total of 7,956 individuals who belonged to the Hitachi Employee 's Health Insurance Group . Of those participants , 5,568 were rescreened 1 year later . When a noncalcified solitary pulmonary nodule ( SPN ) > or= 8 mm was detected on CT screening , a detailed CT scan was carried out approximately 1 month later . RESULTS During the baseline screening , a total of 2,865 noncalcified SPNs were detected among the 7,956 participants . Primary lung cancer was histologically confirmed in 40 patients ( 41 lesions ) . The prevalence was 0.44 % of all participants from the baseline , and 0.07 % from the repeated screening . Thirty-five of 41 tumors were stage I. Current or former smokers represented only 17 of 40 cases . The detection rate was rather high in female participants . CONCLUSION Low-dose spiral CT seems to be a promising method for screening early lung cancer as a part of annual health examinations . Female and nonsmoking subjects should be included in the baseline screening . However , for yearly repeat screening , the participants may be selected on the basis of gender , smoking history , and results at the baseline screening STUDY OBJECTIVE To assess the ability of endobronchial ultrasonography ( EBUS ) using a guide sheath ( EBUS-GS ) to diagnose peripheral pulmonary lesions . METHOD We devised a technique for EBUS-GS covering a miniature probe , and 150 lesions were evaluated in a prospect i ve open study . In this procedure , the probe covered by a guide sheath is introduced into the lesion via the working channel of a bronchoscope . The probe is withdrawn , while the guide sheath is left in situ . A brush or biopsy forceps is introduced through the guide sheath into the lesion . RESULTS One hundred sixteen of 150 EBUS-GS procedures ( 77 % ) were diagnostic . Cases in which the probe was located within the lesion had a significantly higher diagnostic yield ( 105 of 121 cases , 87 % ) than when the probe was located adjacent to it ( 8 of 19 cases , 42 % ) [ p < 0.0001 , chi(2 ) ] . The diagnostic yield from EBUS-GS in lesions < /= 10 mm ( 16 of 21 lesions , 76 % ) , > 10 to < /= 15 mm ( 19 of 25 lesions , 76 % ; p = 0.99 , chi(2 ) ) , > 15 to < /= 20 mm ( 23 of 35 lesions , 66 % ; p = 0.41 , chi(2 ) ) , and > 20 to < /= 30 mm ( 33 of 43 lesions , 77 % ; p = 0.96 , chi(2 ) ) were similar , demonstrating the efficacy of EBUS-GS even in lesions < /= 10 mm in diameter . In 54 of 81 lesions < /= 20 mm , fluoroscopy was not able to confirm whether the forceps reached the lesion . However , the yield was the same with ( 67 % , 18 of 27 lesions ) and without ( 74 % , 40 of 54 lesions ) successful fluoroscopy ( p = 0.96 , chi(2 ) ) . Moderate bleeding occurred in two patients ( 1 % ) ; there were no other complications . CONCLUSIONS EBUS-GS is a useful method for collecting sample s from peripheral pulmonary lesions , even those too small to be visualized under fluoroscopy 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 To evaluate the individual and additive diagnostic yield(s ) of several bronchoscopic sampling techniques for the diagnosis of lung lesions with no corresponding airway abnormalities , consecutive patients with lung nodules or masses were prospect ively evaluated between December 1989 and November 1994 . A CT of the chest  was done in all patients before flexible bronchoscopy ( FB ) .  Size , location , and character of the border of the lesion were determined . During FB , using biplane fluoroscopic guidance , the lesion was localized and following sampling techniques were done : brushing , transbronchial lung biopsy ( TBLB ) , and Sofcor transbronchial needle aspiration ( STBNA ) . Bronchial washings ( BWs ) were collected throughout the procedure . Problems associated with each sampling technique were noted . Forty-nine patients underwent 51 FB .  A diagnosis was established by FB in 36 ( 73 % ) . After a nondiagnostic FB , histologic diagnosis was established in 9 of 13 patients by other methods . A benign or malignant nature of lesion was established in other four patients by clinical follow-up . FB was diagnostic in 32 of 40 ( 80 % ) patients with primary lung cancer , in 3 of 6 ( 50 % ) patients with benign disease , and in 1 of 3 ( 33 % ) patients with metastatic disease to lung . All sampling procedures could be done in 33 of 51 ( 65 % ) FBs . Overall diagnostic yields were as follows : BW , 18 of 51 ( 35 % ) ; brush , 25 of 48 ( 52 % ) ; TBLB , 23 of 40 ( 57 % ) ; and STBNA , 19 of 37 ( 51 % ) . In 12 of 51 ( 24 % ) FBs , only one sample was diagnostic . Lesions with sharp borders had a lower combined diagnostic yield , 13 of 24 ( 54 % ) compared to lesions with fuzzy borders , 20 of 24 ( 83 % ) ( p=0.03 ) . Yield of TBLB in lesions with fuzzy borders , 14 of 18 ( 78 % ) , was higher than the yield for lesions with sharp borders , 6 of 19 ( 32 % ) ( p=0.005 ) . Size of the lesion in centimeters in patients with a positive FB ( 4.55+/- 2.35 ; mean + /-SD ) was significantly larger than in patients with a nondiagnostic FB ( 3.14+/-1.31 ; mean+/-SD ) ( p=0.009 , t test ) . Diagnostic yield was directly related to the size of the lesion . For lesions less than 2 cm , yield was 6 of 11 ( 54 % ) ( p=0.19 ) ; for lesions less than 3 cm , yield was 12 of 21 ( 57 % ) ( p=0.07 ) ; and for lesions greater than 3 cm , yield was 24 of 30 ( 80 % ) . Yield from lesions located in the lower lobe basal segments or the apical segment of upper lobes was lower ( 11/19 , 58 % ) than that from lesions in other parts of the lung ( 25/30 , 83 % ) ( p=0.05 ) . FB was terminated prior to collecting all sample s because of severe bleeding after brushing ( n=3 ) or instability of the patient ( n=4 ) . None of the patients required intubation . There were no pneumothoraces . Diagnostic yield of FB depends on the location , size , character of the border of the lesion , and the ability to perform all sampling methods . Brushing , TBLB , and STBNA should be performed in all patients to give the best diagnostic yield . Routine cytologic examination of BW is unnecessary . Methods other than FB should be considered for lesions 2 cm or less in size , especially when they have a sharp border and /or are located in the basal segment of a lower lobe/apical segment of an upper lobe 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 STUDY OBJECTIVES We evaluated the feasibility and efficacy of transbronchial biopsy ( TBB ) and bronchial brushing by endobronchial ultrasonography ( EBUS ) with a guide sheath ( GS ) as a guide for diagnosing peripheral pulmonary lesions ( PPLs ) without radiographic fluoroscopy . PATIENTS One hundred twenty-one patients with 123 PPLs ( mean diameter , 31.0 mm ) whose bronchoscopic findings were normal . METHODS An EBUS-GS was inserted and advanced to the PPL without fluoroscopy . Once we obtained the EBUS image , the probe was withdrawn and the GS was left in place . TBB and /or bronchial brushing were performed via the GS . When an EBUS image could not be obtained , we changed to the bronchoscopic examination under fluoroscopy . RESULTS Seventy-six of 123 PPLs ( 61.8 % ) were diagnosed by EBUS-GS guidance without fluoroscopy . The diagnostic yield for PPLs > 20 mm in diameter ( 75.6 % ) was significantly higher than that for those < or= 20 mm in diameter ( 29.7 % ; p < 0.01 ) . The PPLs located in the middle lobe and the lingular segment had significantly higher diagnostic yields ( p < 0.05 ) . When the bronchus leading to the PPL was identified on the CT scan , the yield was 79.2 % . Moreover , the solid lesions had a higher diagnostic yield ( 67.0 % ) compared with 
    Output:
    
EBUS is a safe and relatively accurate tool in the investigation of PPLs .
Diagnostic sensitivity of EBUS may be influenced by the prevalence of malignancy in the patient cohort being examined and lesion size .