***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: Summary In March 1981 , 40,318 women in Stockholm , aged 40–64 , entered a r and omized trial of breast cancer screening by single-view mammography alone versus no intervention in a control group of 20,000 women . The attendance rate during the first screening round was 81 per cent and the cancer detection rate was 4.0 per 1000 women . The detection the rate fell to 3.1 per 1000 in the second round , which was completed in October 1985 . During 1986 the controlled design of the study was broken and the contro women were invited once to screening which was completed the same year . A total of 428 cases of breast cancer were thus diagnosed in the study group and 439 in the adjusted control group . After a mean follow-up of 7.4 years the number of breast cancer deaths in the study and control groups was 39 and 30 respectively . The relative risk of breast cancer death ( screening versus control ) was 0.71 ( 95 per cent confidence interval : 0.4–1.2 ) . Among women older than 50 years at entry the relative risk was 0.57 ( 95 per cent confidence interval : 0.3–1.1 ) . Cancer deaths among women under 50 were few and perhaps because of this no mortality reduction was seen in this age group . The estimate of mortality reduction lies between the results from two earlier Swedish r and omized controlled trials To comprehend the results of a r and omised controlled trial ( RCT ) , readers must underst and its design , conduct , analysis , and interpretation . That goal can be achieved only through total transparency from authors . Despite several decades of educational efforts , the reporting of RCTs needs improvement . Investigators and editors developed the original CONSORT ( Consoli date d St and ards of Reporting Trials ) statement to help authors improve reporting by use of a checklist and flow diagram . The revised CONSORT statement presented here incorporates new evidence and addresses some criticisms of the original statement . The checklist items pertain to the content of the Title , Abstract , Introduction , Methods , Results , and Discussion . The revised checklist includes 22 items selected because empirical evidence indicates that not reporting this information is associated with biased estimates of treatment effect , or because the information is essential to judge the reliability or relevance of the findings . We intended the flow diagram to depict the passage of participants through an RCT . The revised flow diagram depicts information from four stages of a trial ( enrolment , intervention allocation , follow- up , and analysis ) . The diagram explicitly shows the number of participants , for each intervention group , included in the primary data analysis . Inclusion of these numbers allows the reader to judge whether the authors have done an intention- to-treat analysis . In sum , the CONSORT statement is intended to improve the reporting of an RCT , enabling readers to underst and a trial 's conduct and to assess the validity of its results A trial in the UK to study the effect on mortality from breast cancer of invitation for annual mammography from the age of 40–41 , has r and omised a total of 160 921 women in the ratio 1 : 2 to the intervention and control arms . All breast cancers diagnosed in the two arms have been identified , and the histology review ed . This paper presents the results of an interim analysis using surrogate outcome measures to compare predicted breast cancer mortality in the two arms based on 1287 cases diagnosed to 31.12.1999 . Due to earlier diagnosis , there is currently an 8 % excess of invasive breast cancers in the intervention arm . The ratio of predicted deaths at 10 years in the intervention arm relative to the control arm , adjusted for this excess diagnosis , ranges from 0.89 ( 95 % confidence interval ( CI ) 0.78–1.01 ) to 0.90 ( 95 % CI 0.80–1.01 ) . Screening from age 40 may result in a lower reduction in breast cancer mortality than that observed in other trials including women below age 50 . This analysis based on surrogate outcome measures suggests that a reduction in breast cancer mortality may be observed in this trial . However , a number of assumptions have been necessary and firm conclusions must await the analysis of observed mortality from breast cancer The Canadian National Breast Screening Study ( CNBSS ) , conducted on women age 40 - 49 , was design ed to evaluate the efficacy of combined annual mammography and physical examination of the breasts in reducing breast cancer mortality in comparison to usual care ( UC ) controls . From January 1980 through March 1985 , 25,214 women were individually r and omized to the mammography/physical exam ( MP ) arm and 25,216 to the UC .  The integrity of the r and omization has been review ed and confirmed to be unbiased . During an average , follow-up of 10.5 years from entry ( range : 8.75 - 13 years ) , 82 women died from breast cancer in the MP arm and 72 in the UC , for a rate ratio of 1.14 ( 95 % confidence interval : 0.83 - 1.56 ) . All-cause mortality was almost identical comparing the two groups ; the nonsignificant excess of breast cancer deaths in the MP arm was balanced by an excess of other cancer deaths in the UC arm Summary The present study investigated : ( 1 ) perception of genetic risk and , ( 2 ) the psychological effects of genetic counselling in women with a family history of breast cancer . Using a prospect i ve design , with assessment pre- and post-genetic counselling at clinics and by postal follow-up at 1 , 6 and 12 months , attenders at four South London genetic clinics were assessed . Participants included 282 women with a family history of breast cancer . Outcome was measured in terms of mental health , cancer-specific distress and risk perception . High levels of cancer-specific distress were found pre-genetic counselling , with 28 % of participants reporting that they worried about breast cancer ‘ frequently or constantly ’ and 18 % that worry about breast cancer was ‘ a severe or definite problem ’ . Following genetic counselling , levels of cancer-specific distress were unchanged . General mental health remained unchanged over time ( 33 % psychiatric cases detected pre-genetic counselling , 27 % at 12 months after genetic counselling).Prior to their genetics consultation , participants showed poor knowledge of their lifetime risk of breast cancer since there was no association between their perceived lifetime risk ( when they were asked to express this as a 1 in x odds ratio ) and their actual risk , when the latter was calculated by the geneticist at the clinic using the CASH model . In contrast , women were more accurate about their risk of breast cancer pre-genetic counselling when this was assessed in broad categorical terms ( i.e. very much lower/very much higher than the average woman ) with a significant association between this rating and the subsequently calculated CASH risk figure ( P= 0.001 ) . Genetic counselling produced a modest shift in the accuracy of perceived lifetime risk , expressed as an odds ratio , which was maintained at 12 months ’ follow-up . A significant minority failed to benefit from genetic counselling ; 77 women continued to over-estimate their risk and maintain high levels of cancer-related worry . Most clinic attenders were inaccurate in their estimates of the population risk of breast cancer with only 24 % able to give the correct figure prior to genetic counselling and 36 % over-estimating this risk . There was some improvement following genetic counselling with 62 % able to give the correct figure , but this information was poorly retained and this figure had dropped to 34 % by the 1-year follow-up . The study showed that women attending for genetic counselling are worried about breast cancer , with 34 % indicating that they had initiated the referral to the genetic clinic themselves . This anxiety is not alleviated by genetic counselling , although women reported that it was less of a problem at follow-up . Women who continue to over-estimate their risk and worry about breast cancer are likely to go on seeking unnecessary screening if they are not reassured Debate continues over the effectiveness of screening by mammography in women below age 50 . We report here on results of screening in the first 10 years of a r and omised trial to study the effect on breast cancer mortality of  invitation to annual mammography  from age 40 to 41 compared to first invitation to the 3-yearly  UK national programme  at age 50–52 . The trial is taking place in 23 NHS breast screening centres . Between 1991 and 1997 , 160 921 women were r and omised in the ratio 1 : 2 to intervention and control arms . Screening is by two views at first screen and single view subsequently ; data on screening up to and including round five are now complete . Uptake of invitation to screening is between 68 and 70 % at all but the latest screening rounds . Rates of referral for assessment are 4.6 % at first screen and 3.4 % at subsequent screens . Invasive cancer detection rates are 0.09 % at first screen , and similar at rescreens until the sixth and later screens . There is little evidence of regular mammography in the trial control arm . The setting of this trial within the NHS breast screening programme should ensure applicability of results to a national programme The results of the Swedish two-county trial of mammographic screening for breast cancer are presented , up date d to December 31 , 1990 , which is an average of 10.8 years follow-up per person . The main result of the trial in terms of breast cancer mortality remained the same : compared with the control group , the group invited to screening had a relative breast cancer mortality of 0.70 ( P = 0.0002 ) with 95 % confidence interval ( 0.58 , 0.85 ) . Analysis of survival showed that relative to the control group , the cancers detected at prevalence screen , incidence screens , and in the interval between screens had a good prognosis , whereas cancers detected in those who had refused screening had a very poor prognosis . When adjusted for tumor size , lymph node status , and tumor grade ( differentiation ) , the better survival associated with incidence screen and interval detection was largely accounted for , indicating that the benefit of incidence screening is largely achieved through the effect of screening on the three prognostic variables , notably size of the tumor . Results indicate that to achieve a substantial mortality reduction , 50 % of screen-detected invasive cancers should be less than 15 mm in diameter , at least 30 % of screen-detected grade 3 tumors should be less than 15 mm , and at least 70 % of screen-detected tumors should not have lymph node metastases . The percentage of grade 3 tumors of a given size should be the same in screen-detected cancers as in clinical ly detected , and breast cancer prevalence at first screen should be at least three times the expected incidence rate in the absence of screening . This should be achieved without the recall rate for further examination exceeding 9 % , and procedures including further imaging techniques and fine needle aspiration or core biopsy should be used before resorting to surgical biopsy . These aims can be achieved in specialist screening centers if particular attention is paid to re sources for screening and diagnostic evaluation , specialist training of clinical and technologic screening staff , and ongoing monitoring of mammographic quality , recall rates , and the attributes of the tumors detected For r and omised population trials the unit of r and omisation is normally the individual person . In some situations , however , investigators take other groups as basic unit and one such design is cluster r and omisation . Considerable attention has been given to this design recently in statistical and epidemiological literature . The Edinburgh r and omised trial of breast cancer screening  is an example which takes general practice s as clusters of patients . The experience of this trial is reported here . Mortality from all causes , cardiovascular disease and lung cancer over the first 5 year period of follow up are examined . We found that spurious mortality differences were present in the analyses , which do not allow for socio-economic status . From examination of methods of adjusting for this , we conclude that allowance can be made at the analysis stage , and it is intended that this approach will be adopted when breast cancer mortality is analysed in the Edinburgh trial . Nevertheless , we recommend that for future studies with outcome related to socio-economic status , r and omisations which use this design be stratified by socio-economic criteria where this is feasible In March 1981 a r and omized single-view mammographic screening for breast cancer was started in the south of Stockholm . The screened population in the first round numbered 40,318 women , and 20,000 women served as a well-defined control group . The age groups represented were 40–64 years , and 80.7 % of the invited women participated in the study . The first round disclosed 128 breast cancers ( 113 invasive and 15 noninvasive ) , or 4.0 per 1,000 women . Mean tumour size was 14.1 mm and axillary lymph node metastases were found in 21.8 % . Fifty-five per cent of the tumours were small ( ⩽10 mm ) or non-invasive , and 71 % were stage I.Participation rates are high in all Swedish trials . The present results differ only slightly from other screening programs ; the percentages of patients with axillary metastases and stage II tumours are similar in the Stockholm , Malmö and Kopparberg/Östergötl and studies . Comparisons of cancer prevalence in the various Swedish screening trials show that , in comparable age groups , there are some differences , even when the differences in the natural cancer incidence are taken into account . A decreased mortality was found recently in a Swedish trial in ages above 50 years but not below . In the Stockholm study more than one-third of the participants were aged 40–49 years To assess how women regard having had a false positive mammogram screening exam  , and the influence that this had on their quality of life , 126 such women were interviewed . Their responses were compared to those of 152 women r and omly selected among screenees with a negative exam . Eighteen months after the screening the reported prevalence of anxiety about breast cancer was 
    Output:
    
Distress increased with the level of invasiveness of the assessment procedure .
Studies using instruments design ed to detect clinical levels of morbidity did not find this effect .
We conclude that the experience of having a false-positive screening mammogram can cause breast cancer-specific psychological distress that may endure for up to 3 years , and reduce the likelihood that women will return for their next round of mammography screening .