***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: Several barriers to  colorectal cancer screening have been identified including limited access to trained endoscopists and highlight insufficient capacity to meet projected dem and for colonoscopies . Two European studies have found that nonphysician providers can perform colonoscopies as safely and accurately as physicians . Training nurse practitioners ( NP ) to perform colonoscopy may be an effective strategy to increase access . The goal of this study was to compare accuracy , safety , and patient satisfaction in screening colonoscopy performed by  board certified gastroenterologists ( GI-MD ) and a gastroenterology trained nurse practitioner ( GI-NP ) . A consecutive sample of average risk participants referred for screening colonoscopy was r and omized to have their procedure performed by either a GI-MD ( n = 100 ) or a GI-NP ( n = 50 ) . Participants completed a preprocedure and postprocedure question naire . Endoscopists completed a postprocedure question naire . Cecal intubation rates , duration of procedure , sedative , and analgesic use , and patient reported procedural pain scores were equivalent among the groups . The GI-NP group had a higher adenoma detection rate compared with the combined GI-MD groups ( 42 % and 17 % , respectively , p = .0001 ) and a higher satisfaction score when compared with the combined GI-MD groups ( mean 5.9 ± 13.81 and 8.6 ± 16.11 , respectively , p = .042 ; visual analog scale 0–100 mm , “ 0 ” = completely satisfied , “ 100 ” = completely dissatisfied ) . There were no immediate complications reported in any group . The properly trained GI-NP in our study performed screening colonoscopy as safely , accurately , and satisfactorily as the GI-MDs . Using well-trained NPs for screening colonoscopy can be an effective strategy to increase access to colorectal screening BACKGROUND & AIMS The use of  nurse endoscopists  to perform flexible sigmoidoscopy is exp and ing , increasing the availability of colorectal cancer screening . However , the effectiveness of this practice has not been studied in r and omized trials . The aim of this trial was to examine the miss rate of polyps , the depth of sigmoidoscope insertion , and the incidence of complications during flexible sigmoidoscopy performed by nurse endoscopists and by gastroenterologists . METHODS Three hundred twenty-eight patients were r and omized to undergo screening flexible sigmoidoscopy performed by a nurse endoscopist or by a gastroenterologist .  Frequency of missed polyps was determined by repeat sigmoidoscopy , performed by a gastroenterologist blinded to the identity of the first endoscopist . Multiple logistic regression analysis identified characteristics associated with missed polyps . RESULTS Gastroenterologists and nurse endoscopists had equivalent miss rates for adenomatous polyps ( 20 % vs. 21 % , respectively ; P = 0.91 ) . No complications occurred in any patient . Gastroenterologists inserted the sigmoidoscope  further than nurse endoscopists ( 61 vs. 55 cm , respectively ; P < 0.00001 ) . Polyp location in the descending colon ( odds ratio , 4.1 ; 95 % confidence interval , 1.7 - 10.3 ) was highly associated with missed polyps . CONCLUSIONS No differences in detection of adenomatous polyps or frequency of complications were found . These data suggest that experienced nurse endoscopists may perform screening flexible sigmoidoscopy as safely and as effectively as gastroenterologists Background : Previous research ers have shown that non-medical endoscopists can perform lower gastrointestinal endoscopy as safely and effectively as medical staff . However , it is not known if upper gastrointestinal endoscopy performed by medical and non-medical endoscopists in clinical practice yields similar results in terms of performance , patient discomfort , and satisfaction . Aim : To determine differences in the yield of diagnosis for significant disease during upper gastrointestinal endoscopy performed by nurse and medical endoscopists and to measure patient discomfort , satisfaction , and attitudes towards future endoscopy . Patients : This two part study included 3009 patients in a retrospective analysis and 480 in a prospect i ve study . Methods : The first part of the study assessed indications for endoscopy  , diagnoses , and procedures performed by medical and nurse endoscopists . In a second prospect i ve study , 480 patients were included to determine the association between endoscopist type and sedation , patient anxiety , discomfort , satisfaction , and attitudes towards future sedation . Results : No patient refused endoscopy by either a nurse or medical endoscopist and there were no complications in either group . Nurses performed 1487 procedures and reported fewer endoscopies as “ normal ” than medical staff ( p=0.006 ) . Multivariate analysis showed that male sex , older age , inpatient status , dysphagia , and gastrointestinal bleeding , but not endoscopist type , were all associated with significant disease . In relation to discomfort and satisfaction , a similar proportion of patients received sedation in both groups ( p=0.81 ) . There were no differences in pre-procedure anxiety ( p=0.61 ) , discomfort during intubation ( p=0.97 ) , discomfort during examination ( p=0.90 ) , or post-procedure examination rating ( p=0.79 ) in patients examined by medical or nurse endoscopists . Conclusion : Experienced nurses perform routine diagnostic gastroscopy safely in everyday clinical practice and with as little discomfort and as much patient satisfaction as medical staff BACKGROUND AND STUDY AIMS Colonoscopy is increasingly performed by nurse endoscopists . We aim ed to assess the endoscopic quality and patient experience of these procedures . PATIENTS AND METHODS This prospect i ve multicenter study analyzed 100 consecutive colonoscopies each for 10 trained nurse endoscopists  with respect to endoscopic quality and patient experience . Colonoscopies were performed under the supervision of a gastroenterologist , using the techniques and protocol s of the participating hospitals . Patient experience was assessed using a question naire . RESULTS Most nurse endoscopists were female ( 90 % ; median age 43 [ range 35 - 49 ] ) . Before the start of the study , they had performed a median of 528 colonoscopies ( range 208 - 2103 ) . For the 1000 patients , mean age was 56 ± 15 years ; 55 % were women ; and 96 % were in class I or II according to the American Society of Anesthesiologists ' physical status classification system .  Colonoscopies were performed for screening or surveillance in 42 % ; for symptomatic indications in 58 % of patients . The unassisted cecal intubation rate was 94 % ; the mean withdrawal time was 10 ± 5 minutes . The adenoma detection rate was 26.7 % . In 229 of the colonoscopies ( 23 % ) , the nurse endoscopists required assistance from the supervising gastroenterologist . The complication rate was 0.2 % : one perforation and one cardiopulmonary complication . The question naire was completed by 734 /1000 patients ( 73 % ) and of these 694 /734 ( 95 % ) were satisfied with the endoscopic procedure . Among the respondents 530 /734 ( 72 % ) had no specific preference for a physician or nurse endoscopist , whereas 113 /734 ( 15 % ) preferred a physician endoscopist , and 91 /734 ( 12 % ) preferred a nurse endoscopist . CONCLUSION The nurse endoscopists performed colonoscopies according to the internationally recognized quality st and ards and with high patient satisfaction Background —Flexible sigmoidoscopy is a technical skill that has been successfully performed by suitably trained colorectal nurse practitioners in the USA . However , no recognised training course exists for nurse practitioners in the UK . Aims —To design and evaluate a training programme for  nurse endoscopists . Methods —A multidisciplinary committee of nurses and clinicians developed a structured programme of study and practice . This involved a staged process of observations , withdrawals , and ultimately , full procedures . Once training had been completed the nurse practitioner was permitted to practice independently . Patients with colorectal symptoms referred for flexible sigmoidoscopy  were examined for the final stages of training and independent practice . A prospect i ve evaluation of the training and practice of the first trained nurse flexible sigmoidoscopist was performed .  Barium enema , video , clinical follow up , and histology  were used to vali date the results of the flexible sigmoidoscopies . Results —The training programme required that 35 observations , 35 withdrawals , and 35 supervised full procedures were performed prior to the development of independent practice . Subsequent to the completion of this programme 215 patients have been examined independently by the nurse practitioner . Ninety three per cent of the examinations were judged successful and pathology was identified in 51 % . The nurse endoscopist successfully identified all “ significant ” pathology whereas barium enema failed to identify pathology in 12.5 % . There were no complications . Conclusion —With suitable training nurse endosocopists are able to perform flexible sigmoidoscopy safely and effectively BACKGROUND Screening by using colonoscopy is recommended in many countries to reduce the risk of death from colorectal cancer . Given the limited supply of medical endoscopists , nurse endoscopists may represent an economic alternative . OBJECTIVE To develop a colonoscopy training program for nurse endoscopists and to evaluate the feasibility of this program . DESIGN Two nurse endoscopists and 1 first-year GI fellow were enrolled in a colonoscopy training protocol , including computer-simulator training , flexible sigmoidoscopies , and colonoscopies under direct supervision . SETTING A single-center prospect i ve study . PATIENTS The first 150 complete colonoscopies of each trainee endoscopist  were evaluated and compared with 150 colonoscopies performed by an experienced endoscopist . MAIN OUTCOME MEASUREMENTS Objective criteria for competency were diagnostic accuracy , cecal-intubation rate , cecal-intubation time , the need for assistance , and complications . Subjective criteria included patient satisfaction , pain , and discomfort scores . RESULTS The nurse endoscopists ' unassisted cecal-intubation rate was 80 % for the first 25 procedures , gradually increasing in subsequent cases to 96 % for the last 25 procedures . The mean cecal-intubation time at the end of the training period was 10 minutes . Cecal-intubation rates and times were comparable between the nurse trainees and the fellow . The patients reported low degrees of pain and discomfort , and high satisfaction scores , irrespective of the type of endoscopist . Diagnostic accuracy of the trainees was good . The complication rate was 0.3 % . LIMITATION Nonr and omized design . CONCLUSIONS This pilot study suggests that nurses can be trained to perform colonoscopy in an effective manner , with results similar to a GI fellow . The learning curve indicated that 150 procedures are required before independent examinations are attempted BACKGROUND Subjects without known colorectal adenomas or cancer constitute a large majority of the population where 85 % of all cases of colorectal cancer are thought to occur . Consequently these people should be considered for screening to decrease mortality from colorectal cancer in the general population . AIMS To estimate the incidence rate of rectosigmoid adenomas in these subjects . METHODS Subjects without adenomas or cancer at a previous examination which had visualised the rectosigmoid underwent a fibre endoscopy every three years . Endoscopic data and population characteristics were collected prospect ively . RESULTS A total of 450 subjects fulfilled the selection criteria ; 287 ( 64 % ) underwent at least two examinations , and 163 had three or more . At the second examination , with a mean delay of 39 months , the incidence rate of rectosigmoïd adenomas was 1.50 % per patient year . The rate was 1.75 % per patient year ( 95 % CI 0.80–3.33 ) at the third endoscopy with an additional mean delay of 38 months . The cumulative incidence rate at six years was 7.3 % ( 95 % CI 4.3–10.3 ) , representing a mean of 1.2 % per patient year . This rate increased with age and was higher for men than for women after age adjustment ( p < 0.03 ) . CONCLUSIONS The incidence rates are very low compared with those of patients with prior adenomas . These results should be considered in establishing rectosigmoid adenoma screening strategies BACKGROUND Open access flexible sigmoidoscopy ( OAFS ) is an integral part of colorectal cancer services . This study compares the impact of two types of open-access flexible sigmoidoscopy services on the utilisation of barium enema and tumour-stage migration . METHODS This was a non-r and omised comparison ( over two one-year periods , four years apart ) of two unselected groups of patients , with different inclusion criteria , in adjacent similarly populated health districts . One offered a nurse practitioner endoscopy service while the other had a doctor-led colorectal clinic . RESULTS The doctor-led service with its broad inclusion criteria detected more colorectal cancers [ 13.2 % versus 0.7 % ; OR = 16.05 ; 2.16 - 119.2 ] . Neither nurse practitioner ( 130 cases ) nor doctor-led ( 262 cases ) flexible sigmoidoscopy reduced the total number of barium enemas [ Odds Ratio ( OR ) = 1.16 ( 95 % CI 1.03 - 1.3 ) ] . 
    Output:
    
Available studies suggest that when non-physicians perform endoscopic procedures , especially lower endoscopies , outcomes and adverse events are in line with those of physicians