***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: Three parallel studies on screening for lung cancer  , supported by the National Cancer Institute , were carried out by the Mayo Clinic , Johns Hopkins Medical Institutions , and Memorial Sloan-Kettering Center from 1971 to 1982 . No significant mortality improvement was established that could be attributed to cytologic screening examinations . Many stage I lung cancers were detected by radiographic screening , with excellent changes for long-term survival . Patients with stage I cancers who were operated on had significantly better survival rates than those who failed to undergo surgery . Statistical modeling , however , indicates that long-term annual screening of a high-risk population would decrease lung cancer mortality by no more than 18 % Background . Ovarian cancer is the fifth most common cause of cancer‐related death in American women . The median age at diagnosis is about 62 years ; incidence rises rapidly after age 60 .  Pelvic examination has been the primary method for detection of ovarian carcinoma . It is insensitive for the detection of early disease , however : most women present with disease beyond the pelvis ( Stages III and IV ) and are not curable with existing techniques . Two new technologies may be useful as screening tools for earlier detection of ovarian cancer . CA 125 is an antigenic determinant expressed on an ovarian cancer cell line . Transvaginal ultrasound ( TVUS ) images the ovaries from within the vagina and can be performed by a technician in about 10 minutes . In small preoperative studies of women with ovarian masses , serum CA 125 levels have been elevated ( typically above 35 U/ml ) in over two‐thirds of cases and in up to 50 % of Stage I cases . The test is not absolutely specific : elevations have been reported with pregnancy , endometriosis , menstruation , benign ovarian tumors , and with cancers of the breast , colon , pancreas , lung , stomach , and liver . Nevertheless , the specificity of CA 125 in postmenopausal women has been reported at about 95 % or more . TVUS provides higher resolving power for ovarian abnormalities than transabdominal ultrasound or physical examination ; however , experience with it is limited . CA 125 and TVUS may be complementary In a controlled investigation the survival prospect s of lung cancer in a population of men aged 40 and over who had been offered six-monthly chest radiographs over a period of three years were compared with lung cancer in a similar population without such x-ray facilities .  The five-year survival rate of lung cancer in the study series was 15 % , and in cases discovered by six-monthly examination 23 % , compared with 6 % in the control series . The average expectation of life after diagnosis was 2·5 years for the test cases and 1·2 for the control cases . Survival declined with age . Of resected lung cancer , 32 % survived five years in the test series and 23 % in the control series . The five-year survival rate for squamous carcinoma and adenocarcinoma in the test series was 28 % and 25 % respectively , compared with 15 % and nil in the control series . On the basis of these results it is concluded that through earlier radiological detection a modest improvement in the prognosis of  lung cancer can be achieved 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 The Mayo Lung Project ( MLP ) was a r and omized , controlled clinical trial of lung cancer screening that was conducted in 9211 male smokers between 1971 and 1983 . The intervention arm was offered chest x-ray and sputum cytology every 4 months for 6 years ; the usual-care arm was advised at trial entry to receive the same tests annually . No lung cancer mortality benefit was evident at the end of the study . We have extended follow-up through 1996 . METHODS A National Death Index-PLUS search was used to assign vital status and date and cause of death for 6523 participants with unknown information . The median survival for lung cancer patients diagnosed before July 1 , 1983 , was calculated by use of Kaplan-Meier estimates . Survival curves were compared with the log-rank test . RESULTS The median follow-up time was 20.5 years . Lung cancer mortality was 4.4 ( 95 % confidence interval [ CI ] = 3.9 - 4.9 ) deaths per 1000 person-years in the intervention arm and 3.9 ( 95 % CI = 3.5 - 4.4 ) in the usual-care arm ( two-sided P : for difference = .09 ) . For participants diagnosed with lung cancer before July 1 , 1983 , survival was better in the intervention arm ( two-sided P : = .0039 ) . The median survival for patients with resected early-stage disease was 16.0 years in the intervention arm versus 5.0 years in the usual-care arm . CONCLUSIONS Extended follow-up of MLP participants did not reveal a lung cancer mortality reduction for the intervention arm . Similar mortality but better survival for individuals in the intervention arm indicates that some lesions with limited clinical relevance may have been identified in the intervention arm The Multiphasic Health Checkup Evaluation Study , a long-term clinical trial , has been completed . A study group of 5156 men and women age 35 - 54 at entry was urged to have annual multiphasic health checkups ( MHCs ) for 16 years . A control group of 5557 comparable subjects was not so urged but was followed up in a comparable fashion . The mean and median number of MHCs per person were 6.8 and 6 , respectively , in the study group and 2.8 and 1 , respectively , in the control group . During 16 years the study group experienced a 30 % reduction ( p less than 0.05 ) in deaths from pre-specified " potentially postponable " causes , largely associated with lower death rates from colorectal cancer and hypertension . This reduction was most pronounced in the early years of the study . The two groups did not differ to a statistically significant degree in mortality from all other causes ( 84 % of total mortality ) or in total mortality . There was no difference in self-reported disability in the overall groups . In the setting of our prepaid health care plan where MHCs were already available on a voluntary basis , a program of urging middle-aged persons to undergo regular MHCs brought about a substantial reduction in mortality from preselected diseases 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 at an earlier stage , more often resectable , and had a significantly better survival than “ interval ” cases diagnosed mainly because of symptoms . Comparison of the 2 groups showed a higher incidence of lung cancer in the intervention group , despite the follow‐up period when both groups received annual examinations . There was no significant difference in mortality between the 2 groups The study was launched in the mid‐1970s to explore the capability of screening by chest X‐ray and sputum cytology to be used as an effective component of the lung cancer control program in the Czech Republic , a Central European country with a high and increasing occurrence of lung cancer in men at that time . A complementary objective of this report is to ascertain whether the cumulative numbers of lung cancer deaths would equalize in the two r and omized groups during a prolonged follow‐up period A prospect i ve and controlled study for early detection of lung cancer in the county of Erfurt with a follow-up of 10 years is presented . A collective of 41,532 males born between 1907 and 1932 was screened by chest fluorography at 6 month intervals  and compared with a control group consisting of 102,348 males of the same age , who were screened at intervals of about 18 months . No significant reduction of overall mortality and of lung cancer mortality was achieved . Semi-annual screening brought about a higher detection rate ( 9%/6.5 % ) , an increase in the resection rate ( 28%/19 % ) and higher 5 and 10 year survival rates ( 52 % ; 27%/39 % ; 19 % ) of resected patients than screening in 18 month intervals . Among those patients who refused resection or were surgically untreatable , the difference in survival rates between the two investigation groups lasted only up to the 12 months barrier . This is regarded as the effect of the lead-time bias . Fluorographic screening is effective only in patients with peripheral cancers . Patients resected for central lung cancers did not show differences in the survival rates . In both investigation groups considered together surgical therapy was possible mainly in those patients who had been detected by screening ( resection rate : 48 % ; 5 yr survival rate : 26.9 % ) . The resection rate of all the others amounted to 9 % , the 5 yr survival rate to 1.4 % . Therefore we consider fluorography to time as the only chance for lung cancer control of high risk groups in spite of the absence of reduction of lung cancer mortality The Early Lung Cancer Action Project ( ELCAP ) is design ed to evaluate baseline and annual repeat screening by low radiation dose computed tomography ( low‐dose CT ) in persons at high‐risk for lung cancer . The authors report on the baseline screening experience . For full evaluation of screening , they await the results of annual repeat screening Objectives To examine whether age at entry , history of cigarette smoking , exposure to non-tobacco lung carcinogens , or previous pulmonary illnesses were confounders or effect modifiers of the relation between screening and lung cancer mortality in the Mayo Lung Project . Setting —The Mayo Lung Project was a r and omised , controlled , clinical trial conducted between 1971 and 1986 in 9211 male smokers over the age of 45 in Minnesota ( USA ) . The group screened received chest x ray examination and sputum cytology every four months for six years . The unscreened group were recommended to obtain usual care ( annual chest x ray examination and sputum cytology ) . After follow up , lung cancer mortality was similar in both groups . Methods —Proportional hazard models were used to analyse data . A variable was considered a confounder if its inclusion in a model changed the rate ratio for  screening  by more than 15 % ; a variable was considered an effect modifier if its stratum-specific rate ratio for screening differed by a factor of two . Results None of the four aforementioned variables changed the rate ratio associated with screening  ( 1.07 ) by more than 2 % . The effect of screening  may have differed by years smoked ( rate ratio for smoking fewer than 30 years 2.4 ; rate ratio for smoking 30 or more years 1.0 ) , though we suspect that this result occurred by chance . Conclusion Adjustment for or stratification by four established lung cancer risk factors did not alter the original findings of the Mayo Lung Project 
    Output:
    
The current evidence does not support screening for lung cancer with chest radiography or sputum cytological examination .
Frequent chest radiography might be harmful .