***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: OBJECTIVE The purpose of this study was to determine how often physician-performed high-resolution sonography can detect nonpalpable breast lesions not revealed by mammography . A sonographic classification scheme was tested for its accuracy in predicting malignancy of incidentally detected breast lesions . SUBJECTS AND METHODS Six thous and one hundred thirteen asymptomatic women with breast density grade s 2 - 4 and 687 patients with palpable or mammographically detected breast masses underwent sonography as an adjunct to mammography . All sonographically detected , clinical ly and mammographically occult breast lesions that were not simple cysts were prospect ively classified into benign , indeterminate , or malignant categories . Diagnoses were confirmed by sonographically guided fine-needle aspiration or core needle biopsy . RESULTS In 6113 asymptomatic women , 23 malignancies  in 21 patients were detected with sonography only ( prevalence , 0.31 % ) . Five additional malignant lesions were found in patients with a malignant ( n = 3 ) or a benign ( n = 2 ) palpable or mammographically detected index lesion . The mean size of invasive malignancies detected only by sonography was 9.1 mm , which was not significantly different from the mean size of invasive cancers detected by mammography ( p = .07 ) . The sensitivity of the prospect i ve sonographic classification for malignancy was 100 % , and the specificity was 33.5 % . CONCLUSION The use of high-resolution sonography as an adjunct to mammography in women with dense breasts may lead to detection of a significant number of otherwise occult malignancies that are no different in size from nonpalpable mammographically detected lesions . Prospect i ve classification of these lesions based on sonographic characteristics results in a significant reduction in number of unnecessary biopsies performed Abstract Background : Controversies over the frequency and intensity of the follow-up care of breast cancer patients exist . Some physicians have adopted an intensive approach to follow-up care that consists of frequent laboratory tests and routine imaging studies , including chest radiographs , bone scans , and CT scans , whereas others have established a minimalist approach consisting of only history , physical examinations , and mammograms . Objectives : Our objective was to evaluate the role of intensive follow-up on detection of breast cancer recurrence and to examine the impact of follow-up on overall survival . Methods : During a 10-year period ( 1986–1996 ) , 129 patients with recurrent disease were identified from a prospect i ve data base of 1898 breast cancer patients . The patients with recurrent disease were divided into minimalist or intensive groups according to method of detection . Results : Twenty-seven of 126 ( 21 % ) patients were assigned to the intensive method of detection group ( LFT , CEA , CA 15 - 3 , chest radiograph , CT scan , and bone scan ) ; 99 of 126 ( 79 % ) patients were assigned to the minimal detection group ( history , physical examination , and mammography ) . Distant disease to the bone was the most common initial tumor recurrence , at 27 % . History , physical examination , and mammography detected recurrent cancer in approximately the same amount of time as LFTs , tumor markers , CT scans , and chest radiographs ( P=.960 ) . When the recurrent patients were divided into intensive and minimalist groups and analyzed by time to detection of recurrence , there was no significant difference between the time to detection in those recurrences detected by intensive methods and those recurrences detected by minimalist methods (P=.95).The independent variables age , tumor size , type of surgery , number of positive nodes , time to recurrence , method of detection , and site of recurrence ( regional or distant ) were subject to univariate and multivariate analysis by the Cox proportional hazards model . Only two variables had an impact on survival by multivariate analysis : early timing of the recurrence ( P=.0011 ) and the site of the recurrence ( P=.02 ) . Timing was defined as early ( ⩽365 days from the time of diagnosis to recurrence ) or late ( ⩾365 days from the time of diagnosis to recurrence ) . Early recurrence was the first variable found to be significant on stepwise forward regression analysis . The primary site of recurrence was significant at step two . The method of detection — intensive or minimal — did not significantly affect survival ( P=.18 ) . Conclusions : There is no survival benefit to routine intensive follow-up regimens in detecting recurrent breast cancer . Expensive diagnostic tests such as bone scans , CT scans , and serial tumor markers are best used for detection of metastasis in symptomatic patients Results from the completed treatment analysis of the ATAC ( Arimidex , Tamoxifen alone or in combination ) trial indicated that anastrozole was significantly superior to tamoxifen in terms of efficacy and safety in the adjuvant treatment of postmenopausal women with hormone receptor-positive ( HR+ ) early breast cancer . On the basis of these results , this study estimated the cost-effectiveness of anastrozole vs tamoxifen , from the perspective of the UK National Health Service ( NHS ) . A Markov model was developed using the 5-year completed treatment analysis from the ATAC trial ( IS RCT N18233230 ) , as well as data obtained from published literature and expert opinion . Re source utilisation data and associated costs ( 2003–4 UK£ ) were compiled from st and ard sources and expert opinion . Utility scores for a number of health states were obtained from a cross-sectional study of 26 representative patients using the st and ard gamble technique . The utility scores were then inserted into the model to obtain cost per quality adjusted life-year ( QALY ) gained . Costs and benefits were discounted at recommended annual rates of the UK Treasury ( 3.5 % ) . Modelled for 25 years , anastrozole , relative to generic tamoxifen , was estimated to result in 0.244 QALYs gained per patient at an additional cost of £ 4315 per patient ) . The estimated incremental cost-effectiveness of anastrozole compared with tamoxifen was £ 17 656 per QALY gained . There was a greater than 90 % probability that the cost-effectiveness of anastrozole was below £ 30 000 per QALY gained and of the order of 65 % that it was below £ 20 000 per QALY gained . The results were robust to all parameters tested in sensitivity analysis . Compared with commonly accepted thresholds , anastrozole is a cost-effective alternative to generic tamoxifen in adjuvant treatment of postmenopausal women with HR+ early breast cancer from the UK NHS perspective Background Postal surveys are a frequently used method of data collection in health services research . Low response rates increase the potential for bias and threaten study validity . The objectives of this study were to estimate current response rates , to assess whether response rates are falling , to explore factors that might enhance response rates and to examine the potential for non-response bias in surveys mailed to healthcare professionals . Methods A r and om sample of postal or electronic surveys of healthcare workers ( 1996 - 2005 ) was identified from Medline , Embase or Psycinfo data bases or Biomed Central . Outcome measures were survey response rate and non response analysis . Multilevel , multivariable logistic regression examined the relationship between response rate and publication type , healthcare profession , country and number of survey participants , question naire length and use of reminders . Results The analysis included 350 studies .  Average response rate in doctors was 57.5 % ( 95%CI : 55.2 % to 59.8 % ) and significantly lower than the estimate for the prior 10 year period . Response rates were higher when reminders were sent ( adjusted OR 1.3 ; 95%CI 1.1 - 1.6 ) but only half the studies did this . Response rates were also higher in studies with fewer than 1000 participants and in countries other than US , Canada , Australia and New Zeal and . They were not significantly affected by publication type or healthcare profession ( p > 0.05 ) . Only 17 % of studies attempted assessment of possible non-response bias . Conclusion Response rates to postal surveys of healthcare professionals are low and probably declining , almost certainly leading to unknown levels of bias . To improve the informativeness of postal survey findings , research ers should routinely consider the use of reminders and assess potential for non-response bias OBJECTIVES To assess whether omission of postoperative radiotherapy in women with ' low-risk ' axillary node negative breast cancer ( T0 - 2 ) treated by breast-conserving surgery and endocrine therapy improves quality of life and is more cost-effective . DESIGN A r and omised controlled clinical trial , using a method of minimisation balanced by centre , grade of cancer , age , lymphatic/vascular invasion and preoperative endocrine therapy , was performed . A non-r and omised cohort was also recruited , in order to complete a comprehensive cohort study . SETTING The setting was breast cancer clinics in cancer centres in the UK . PARTICIPANTS Patients aged 65 years or more were eligible provided that their cancers were considered to be at low risk of local recurrence , were suitable for breast-conservation surgery , were receiving endocrine therapy and were able and willing to give informed consent . INTERVENTIONS The st and ard treatment of postoperative breast irradiation or the omission of radiotherapy . MAIN OUTCOME MEASURES Quality of life was the primary outcome measure , together with anxiety and depression and cost-effectiveness . Secondary outcome measures were recurrence rates , functional status , treatment-related morbidity and cosmesis . The principal method of data collection was by question naire , completed at home with a research nurse at four times over 15 months . RESULTS The hypothesised improvement in overall quality of life with the omission of radiotherapy was not seen in the EuroQol assessment or in the functionality and symptoms summary domains of the European Organisation for Research in the Treatment of Cancer ( EORTC ) scales . Some differences were apparent within subscales of the EORTC question naires , and insights into the impact of treatment were also provided by the qualitative data obtained by open-ended questions . Differences were most apparent shortly after the time of completion of radiotherapy . Radiotherapy was then associated with increased breast symptoms and with greater fatigue but with less insomnia and endocrine side-effects . Patients had significant concerns about the delivery of radiotherapy services , such as transport , accommodation and travel costs associated with receiving radiotherapy . By the end of follow-up , patients receiving radiotherapy were expressing less anxiety about recurrence than those who had not received radiotherapy .  Functionality was not greatly affected by treatment . Within the r and omised controlled trial , the Barthel Index demonstrated a small but significant fall in functionality with radiotherapy compared with the no radiotherapy arm of the trial . Results from the non-r and omised patients did not confirm this effect , however . Cosmetic results were better in those not receiving radiotherapy but this did not appear to be an important issue to the patients . The use of home-based assessment s by a research nurse proved to be an effective way of obtaining high- quality data . Costs to the NHS associated with postoperative radiotherapy were calculated to be of the order of 2000 pounds per patient . In the follow-up in this study , there were no recurrences , and the quality of life utilities from EuroQol were almost identical . CONCLUSIONS Although there are no differences in overall quality of life scores between the patients treated with and without radiotherapy , there are several dimensions that exhibit significant advantage to the omission of irradiation . Over the first 15 months , radiotherapy for this population is not a cost-effective treatment . However , the early postoperative outcome does not give a complete answer and the eventual cost-effectiveness will only become clear after long-term follow-up . Extrapolations from these data suggest that radiotherapy may not be a cost-effective treatment unless it results in a recurrence rate that is at least 5 % lower in absolute terms than those treated without radiotherapy . Further research is needed into a number of areas including the long-term aspects of quality of life , clinical outcomes , costs and consequences of omitting radiotherapy Goal To ascertain outcomes of surveillance mammography ( SM )  following treatment of early stage unilateral primary breast cancer ( PBC ) in a population based case series . Methods R and om sample s from all 12,279 women having breast surgery within 4 months after diagnosis of PBC , between July 1991 and December 1993 in Ontario , were drawn from a data base created by deterministic linkage of PBC files from the Ontario Cancer Registry ( OCR ) with episodes of breast surgery extracted from the hospital Discharge Abstract Data base ( DAD ) , and mammography from the Ontario physician billings data base ( OHIP ) . Among women having ≥1 episode(s ) of breast surgery subsequent ( SBS ) to the date of diagnosis up to December 2000 , a sample of 1,200/5,064 ( 23.7 % ) was drawn , and among women with no SBS , a sample of 400/7,215 ( 5.5 % ) . Among these two sample s , operative , pathology , and mammography reports were abstract ed from original charts . Treatments were abstract ed and categorized . Women with complete data for Stages 1 and 2 unilateral PBC were included . From the subsequent surgery sample , 609/1,200 ( 50.8 % ) were excluded because of simultaneous or sequential bilateral breast cancers or mastectomies within 6 months , missing stage information , Stage 3 or 4 PBC , or missing primary charts . From the no subsequent surgery sample , 90/400 ( 22.5 % ) were excluded by the same criteria . Episodes of bilateral 2-view X-ray mammography , beginning ≥6 months after the diagnosis of unilateral PBC , and if multiple , at least 11 months apart , and not prompted by a clinical concern or symptom , were classified as SM . We confirmed episodes of cancer recurrence within the ipsilateral conserved breast ( CRICB ) and metachronous contralateral primary breast cancer ( CPBC ) ≥6 months after the diagn 
    Output:
    
Data set analysis showed that IBTR has an adverse effect on survival .
Furthermore , women experiencing a second tumour measuring > 20 mm in diameter were at a significantly greater risk of death than those with no recurrence or those whose tumour was < 10 mm in diameter .
There was no useable evidence contained in the Breast Cancer Registry data base to assess the effectiveness of surveillance mammography directly .
Surveillance is likely to improve survival and patients should gain maximum benefit through optimal use of re sources , with those women with a greater likelihood of developing IBTR or MCBC being offered more comprehensive and more frequent surveillance .