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ABSTRACT BACKGROUND: The gold standard test for colorectal cancer screening the colonoscopy. Although this is the test of choice, colonoscopy misses a significant number of lesions, mainly in the proximal colon. With the purpose of reducing the number of lesions missed, new techniques have been studied, amongst them, retroflexed view in the right side of the colon and the second direct forward view. OBJECTIVE: Assessing the safety of the retroview in the proximal colon (cecum and ascending colon), its impact on the detection of lesions in the proximal colon and its advantage over the double right forward view using adenoma detection rate and adenoma miss rate. METHODS: Three hundred and ninety-three patients who came to Hospital Mater Dei to undergo colonoscopy from March to July 2017, prospectively. Out of these, 372 were included in the study based on the following exclusion criteria: being under 18 years of age, inadequate bowel preparations (Boston scale <7), history of colectomy, inflammatory bowel disease or polypoid diseases. First, an endoscopist inserted the colonoscope into the cecum and examine the cecum and the ascending colon with a forward view twice. In the third insertion into the cecum, retroflexed view was performed, cecal mucosa was examined until the hepatic flexure in search of polyps missed on forward view. All lesions found were resected and sent for histological analysis. RESULTS: In 334 (89.8%) patients, retroflexed view was performed successfully, 65.8% of failures were attributed to the loops of the device which prevented the maneuver. The direct view identified 175 polyps in the proximal colon in 102 people. Retroflexed view detected 26 polyps missed by the direct view in 24 (6.5%) people, with a missing rate of 12.9% in the test with only the forward view. Out of the 26 polyps found in retroview, 21 (80.76%) were adenomas, one of them with a high-grade dysplasia. Eleven patients had polyps seen only in retroflexed view. Retroview has increased the polyp detection rate from 27.41% to 31.72% and the adenoma detection rate from 21.77% to 25%. The adenoma miss rate by the double direct view was 12.8%. Without the retroview, one polyp in every 13.91 colonoscopies would be missed (number needed to treat - NNT=13.91). There was no adverse event. CONCLUSION: The retroflexed view technique in the proximal colon was shown to be safe, fast and feasible in most cases. It increased the adenoma detection rate and was shown to be advantageous in this study wit benefit beyond the double direct view.
RESUMO CONTEXTO: O exame padrão ouro para rastreamento de câncer colorretal é a colonoscopia. Apesar de ser o exame de escolha, a colonoscopia perde um número não desprezível de lesões, principalmente no cólon proximal. Com a intenção de reduzir a perda de lesões, novas técnicas são estudadas, dentre elas, a retroflexão em cólon direito e a segunda visão frontal direta. OBJETIVO: Avaliar a segurança da retrovisão no cólon proximal (ceco e cólon ascendente), o seu impacto na detecção de lesões em cólon proximal e sua superioridade sobre a dupla visão frontal direta usando taxa de detecção de adenoma e taxa de adenoma perdido. MÉTODOS: Foram avaliados 393 pacientes de forma prospectiva que procuraram o Hospital Mater Dei para realizar colonoscopia entre março e julho de 2017. Desses, 372 foram incluídos baseados nos critérios de exclusão: menores de 18 anos, preparos intestinais inadequados (escala de Boston <7), com antecedente de colectomia, doença inflamatória intestinal ou síndromes polipoides. Primeiramente um endoscopista realizou a inserção do colonoscópio até o ceco e examinou o ceco e o cólon ascendente em visão frontal por duas vezes. Na terceira reinserção até o ceco era realizada a retroflexão e inspeção da mucosa do ceco até a flexura hepática em busca de pólipos perdidos à visão frontal. Todas lesões encontradas foram ressecadas e enviadas para análise histológica. RESULTADOS: Em 334 (89,8%) pacientes a retroflexão foi realizada com sucesso, 65,8% dos insucessos foram atribuídos a alças no aparelho que impediram a manobra. A visão direta identificou 175 pólipos no cólon proximal em 102 pessoas. A retroflexão detectou 26 pólipos perdidos pela visão direta em 24 (6,5%) pessoas, com uma taxa de perda de 12,9% no exame apenas em visão frontal. Dos 26 pólipos encontrados em retrovisão, 21 (80,76%) eram adenomas, um deles com displasia de alto grau. Onze pacientes tinham pólipos vistos apenas em retroflexão. A realização da retrovisão aumentou a taxa de detecção de pólipo de 27,41% para 31,72% e a taxa de detecção e adenomas de 21,77% para 25%. A taxa de adenoma perdido pela dupla visão direta foi de 12,8%. Se a retrovisão não fosse realizada, um pólipo a cada 13,91 colonoscopias seria perdido (NNT=13,91). Não houve nenhum evento adverso. CONCLUSÃO: A técnica de retroflexão em cólon proximal mostrou-se segura, rápida e factível na maioria dos casos. Ela aumentou a taxa de detecção de adenomas e mostrou-se soberana neste estudo com benfeitorias além da dupla visão direta.
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Humans , Adolescent , Colonic Polyps/diagnostic imaging , Colonic Neoplasms/diagnostic imaging , Colonoscopy , Tertiary Care CentersABSTRACT
Objective To set up a computer-assisted polyp detection system under colonoscopy,and to preliminarily verify its effectiveness.Methods Based on Faster R-CNN algorithm and the open source implementation of the open source framework tensorflow and Faster R-CNN,a computer-assisted polyp detection system under colonoscopy was constructed.According to the size and difficulty of the training set,five test groups were set up:test group one,two,three and four contained 1 000,2 000,4 000 and 6 000 training samples,respectively.Test group five increased the probability of selecting the difficult samples based on 6 000 training samples.In different training sets,the sensitivity,specificity,other classification evaluation parameters,and the evaluation parameters of target detection such as recall and precision of this polyps detection system were calculated.Results Classification evaluation parameters showed that the sensitivities of test group one,two,three,four and five were 90.1％,93.3％,93.3％,93.3 ％ and 93.5 ％,respectively,and the difference was statistically significant (x2 =25.324,P＜0.01).The sensitivities of test group two,three,four and five were all higher than that of test group one,and the differences were statistically significant (x2 =13.964,13.508,13.508 and 13.386,all P＜ 0.006 25).There were no significant differences in specificity and positive predictive value among test groups (both P＞0.05).The negative predictive values of test group one,two,three,four and five were 90.4％,93.3％,93.3％,93.3％ and 93.5％,respectively,and the differences were statistically significant (x2 =21.862,P＜0.01).The negative predictive values of test group two,three,four and five were higher than that of test group one,and the differences were statistically significant (x2=11.447,11.564,11.755,13.760;all P＜0.006 25).As the training sample size increased from 1 000 to 2 000,the area under curve (AUC) increased by 2％,and further increased the sample size to 6 000,AUC increased by less than 1 ％.At this point maintaining the same sample size while increasing the proportion of difficult samples,AUC increased by 0.4％.The results of evaluation parameters of target detection showed that the recall rate of each test group was 73.6％,79.8％,79.5％,79.8％ and 83.3％,respectively,and the differences were statistically significant (x2 =71.936,P＜0.01).Among them,the recall rates of test group two,three and four were higher than that of test group one,and the differences were statistically significant (x2 =25.960,23.492 and 25.960,all P＜0.006 25),and the recall rate of test group five was higher than those of test group one,two,three and four,and the differences were statistically significant (x2=67.361,9.899,11.527 and 9.899;all P＜0.006 25).In addition,the precision rates of test group one,two,three,four and five were 87.9％,85.3％,90.2％,91.4％ and 89.2％,respectively,and the difference was statistically significant (x2=48.194,P＜0.01).The precision rates of test group three and five were higher than that of test group two,and the differences were statistically significant (x2 =24.508 and 15.223,both P＜0.006 25),and the precision rate of test group four was higher than those of test group one and two,and the differences were statistically significant (x2=13.524 and 39.120,both P＜0.006 25).As samples size and training difficulty increased,the values of F1-score and mean average precision increased steadily.Conclusions This study initially constructed a computer-assisted polyp detection system under colonoscopy.Currently the maximum sensitivity reached 93.5％,and the maximum recall rate reached 83.3％.Increasing the training set size may improve the polyp detection result to a certain degree,however it will reach a bottleneck.At this time,increasing the training difficulty can further improve the detection scores,especially the recall rate.
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Objective To investigate the clinical application prospect of water exchange colonoscopy.Methods A total of 300 outpatients who underwent unsedated colonoscopy were randomized to the WEC group (n =150)or the AIC group(n =150).The maximum pain score, insertion time, the cecal intubation rate and the polyp detection rate were reported by an assistant during the insertion phase and at the end of colonoscopy.Results The maximum abdominal pain scores were 1.77 ± 1.29 in the WEC group and 2.84 ± 1.55 in the AIC group with significant difference (P =0.000).The intubation time of WEC was longer than that of AIC (11.91 ± 3.58 VS 8.03 ± 3.19 ,P =0.000)with no significant difference.There was no significant difference in the cecal access rate between the two groups(97.3％ VS 94.0％ ,P =0.157).The polyp detection of WEC was higher than that of AIC (16.7％ VS 10.0％, P =0.089).In the post abdominal operation subject of colonoscopy procedure, WEC had higher rate of cecal intubation than AIC ,the maximum abdominal pain score were 2.25 ± 1.63 in the WEC group,lower than 3.48 ± 1.45 in the AIC group.Conclusion Water exchange colonoscopy can alleviate patients' abdominal pain symptoms, but with longer insertion time.There are no significant difference in the cecal access rate and the polyp detection rate between two groups.For difficult colonoscopy, water exchange colonoscopy is helpful to increase the rate of cecal intubation.
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BACKGROUND/AIMS: Colorectal cancer (CRC) develops from colonic adenomas. Type 2 diabetes mellitus (DM) is associated with a higher risk of CRC and metformin decreases CRC risk. However, it is not certain if metformin affects the development of colorectal polyps and adenomas. This study aimed to elucidate if metforminaffects the incidence of colonic polyps and adenomas in patients with type 2 DM. METHODS: Of 12,186 patients with type 2 DM, 3,775 underwent colonoscopy between May 2001 and March 2013. This study enrolled 3,105 of these patients, and divided them in two groups: 912 patients with metformin use and 2,193 patients without metformin use. Patient clinical characteristics, polyp and adenoma detection rate in the two groups were analyzed retrospectively. RESULTS: The Colorectal polyp detection rate was lower in the metformin group than in the non-meformin group (39.4% vs. 62.4%, P<0.01). Colorectal adenoma detection rate was significantly lower in the metformin group than in the non-metformin group (15.2% vs. 20.5%, P<0.01). Fewer advanced adenomas were detected in the metformin group than in the non-metformin group (12.2% vs. 22%, P<0.01). Multivariate analysis identified age, sex, Body mass index and metformin use as factors associated with polyp incidence, whereas only metforminwas independently associated with decreased adenoma incidence (Odd ratio=0.738, 95% CI=0.554-0.983, P=0.03). CONCLUSIONS: In patients with type 2 DM, metformin reduced the incidence of adenomas that may transform into CRC. Therefore, metformin may be useful for the prevention of CRC in patients with type 2 DM.
Subject(s)
Humans , Adenoma , Body Mass Index , Colon , Colonic Polyps , Colonoscopy , Colorectal Neoplasms , Diabetes Mellitus, Type 2 , Incidence , Metformin , Multivariate Analysis , Polyps , Retrospective StudiesABSTRACT
BACKGROUND/AIMS: A few studies showed that hood-cap assisted colonoscopy (CAC) had improved cecal intubation rate and cecal intubation time but did not help in finding colon polyps in comparison with conventional colonoscopy (CC). However, other studies have shown different results. Therefore, we investigated the efficacy of CAC for the cecal intubation time and polyp detection rate. METHODS: Patients for colonoscopy in Busan St. Mary's Medical Center were enrolled to this randomized controlled trial between July 2010 and September 2010. The evaluated outcomes were polyp detection rate, adenoma detection rate, and cecal intubation time in all patients, in difficult cases (history of previous abdominal or pelvic surgery, obesity, old age), and in the expert and non-expert groups. RESULTS: A total of 260 patients enrolled in this study were randomly allocated to the CAC group (n=130), or CC group (n=130). The overall cecal intubation time was shorter in the CAC group (5.7+/-3.4 min vs. 7.8+/-5.7 min, P<0.001). The polyp detection rate was higher in the CAC group (58.4% vs. 43%, P=0.008). The cecal intubation time in the expert and non-expert groups were shorter in the CAC group (expert: 4.1+/-2.2 min vs. 5.5+/-2.0 min, P=0.001; non-expert: 6.7+/-3.7 min vs. 9.4+/-5.9 min, P=0.001). CONCLUSIONS: The use of CAC improved the detection rate of colon polyps and shortened the cecal intubation time for both the expert and non-expert groups.
Subject(s)
Humans , Adenoma , Colon , Colonoscopy , Intubation , Obesity , PolypsABSTRACT
BACKGROUND/AIMS: The aim of this study was to assess the effects of endoscopy nurse participation on polyp detection rate (PDR) and adenoma detection rate (ADR) of second-year fellows during screening colonoscopies. METHODS: This was a single-center, prospective, randomized study comparing a fellow alone and a fellow plus an endoscopy nurse as an additional observer during afternoon outpatient screening colonoscopies. The primary end points were PDR and ADR. RESULTS: One hundred ninety-one colonoscopies performed by a fellow alone and 192 colonoscopies performed by a fellow plus an endoscopy nurse were analyzed. The PDR was significantly higher when the nurse was involved (53.1% vs. 41.3%, p or =2 polyps, advanced adenomas, polyp size, polyp location, and polyp shapes between the two groups. There was no difference in the PDR according to the level of experience of the endoscopy nurse. CONCLUSIONS: Endoscopy nurse participation as an additional observer during screening colonoscopy performed by second-year fellow increases the PDR; however, the level of experience of the nurse was not an important factor.
Subject(s)
Humans , Adenoma , Colonoscopy , Endoscopy , Mass Screening , Outpatients , Polyps , Prospective StudiesABSTRACT
BACKGROUND/AIMS: The adenoma detection rate (ADR) has been proposed as a quality indicator of colonoscopy; however, ADR cannot be measured easily with commonly used endoscopy reporting systems because substantial time and effort is required to acquire data from histologic assessments. The purpose of this study was to determine if polyp detection rate (PDR) could be used as a valid proxy for ADR. METHODS: A total of 1,156 consecutive, asymptomatic, individuals of average risk between 50 and 75 years-of-age who underwent screening colonoscopies at four tertiary medical centers by 27 gastroenterologists were included in this study. Each individual endoscopist performed at least 10 colonoscopies during the study period. The ADR and PDR were calculated as the proportion of an endoscopist's cases with an adenoma or polyp divided by the total number of colonoscopies. Pearson's correlation coefficient and the intraclass correlation coefficient were used to determine the level of agreement between ADR and PDR. RESULTS: The mean PDR and ADR for endoscopists was 47.4% (range, 21.7-75.0) and 36.5% (range, 13.0-66.7), respectively. There was a strong correlation between PDR and ADR (Pearson's correlation coefficient 0.94, P<0.001) and there was also good agreement between performance quintiles defined by ADR and PDR (intraclass correlation coefficient 0.94, P<0.001). CONCLUSIONS: PDR is a valid proxy for ADR and may be useful for quality assurance at centers where ADR cannot be easily measured.
Subject(s)
Humans , Adenoma , Colonoscopy , Endoscopy , Mass Screening , Polyps , Proxy , Quality Indicators, Health CareABSTRACT
BACKGROUND/AIMS: The colonoscopic withdrawal time has been proposed as a quality indicator for colonoscopy, and this is based on the recent evidence that the Colon withdrawal time is associated with adenoma detection rate. In this study, we examined the difference of the polyp detection rates between practicing endoscopists, and we analysed certain factors that might lead to such differences, and particularly the colonoscopic withdrawal time. METHODS: We retrospectively evaluated the colonoscopic procedures that were performed by 7 second-year GI fellows at Hanyang University Guri Hospital. A total of 1,515 colonoscopies were assessed for the polyp detection rate, the insertion time, the withdrawal time, bowel preparation, the size of the detected polyps and the location of polyps. RESULTS: The median withdrawal time for the case with no polyps removed was 3.6 to 7.1 minutes. There was a strong positive correlation between the colonoscopic withdrawal times and the polyp detection rates (p<0.001). Furthermore, a longer withdrawal time resulted in discovering a higher percentage of small polyps. On comparing groups, the group of colonoscopists with a withdrawal time longer than 6 minutes had a higher rate of detecting polyps (30.7% vs 18.4%, p<0.001). CONCLUSIONS: There is wide range of polyp detection rates among practicing colonoscopists and there is strong positive correlation between the colonoscopic withdrawal times and the rate of detecting polyps. A long enough withdrawal time, perhaps 7 minutes, is needed to raise the rate of detecting polyps during colonoscopy.