Proximal Adenoma Detection Rate Research Articles

Feasibility of Water Colonoscopy in a Canadian Community Population

Purpose: Water-aided methods, either by immersion or exchange, minimize pain during colonoscopy, thereby reducing or eliminating sedation requirements. Water exchange, in particular, also enhances adenoma detection rates (ADR) when compared to air insufflation. Previous descriptions of the technique in North America involved predominantly male VA populations. In the context of a performance improvement program, to establish the feasibility of using water-aided methods in one busy GI community practice in Canada. Methods: At the Kelowna General Hospital, over a 13 month period patients presenting for colonoscopy, for all indications, were offered a colonoscopy using the water-aided methods and an option to attempt the procedure without sedation. The method of water immersion was performed in the first 1-2 months and replaced exclusively with water exchange thereafter. Communication with a knowledgeable trainer via email facilitated learning and conversion to the water exchange method. Colonoscopy was performed by two endoscopists. Standard colonoscopes were used. Water was infused with a paddle pump. Clean water was infused to facilitate insertion while suctioning cloudy water. Once cecal intubation was achieved air insufflation allowed examination and polyp removal on withdrawal. Procedural outcomes were recorded. Results: 200 (106M/94F) water-aided colonoscopies were completed, 81 for screening, 64 for surveillance and 55 were diagnostic. The intent-to-treat cecal intubation rate was 93%. 97 patients (62M/35F) of 102 (64M/38F), 95% who consented to the procedure without sedation successfully completed it without on demand sedation. Average insertion time was 15 min with an average withdrawal time of 6 min (excluding polypectomy) for an overall average procedure time of 21 min for all indications. The overall ADR for patients with a screening/surveillance indication was 30% (43/145), 36% (31/87) in males and 21% (12/58) in females with an overall proximal ADR of 21% (31/145), 25% (22/87) in males and 16% (9/58) in females and an overall sessile serrated polyp detection rate of 4% (5/145). Two advanced adenomas and one cancer were identified in 2% of patients (3/145). Conclusion: Water-aided methods are feasible and can be integrated into a busy community practice. Rates of cecal intubation are similar to published results. ADR are higher than recommended quality standards (male 25%, female 15%). These results are instrumental in generating funding support provided by the Canadian Association of Gastroenterology and the Canadian Digestive Health Foundation to conduct a prospective RCT to evaluate the approach of extended, unsedated flexible sigmoidoscopy using water exchange as a universal screening examination.

795 Combined Dye (Indigocarmine) and Water Method vs. Water Method Alone Further Enhanced Proximal Adenoma Detection Rate (ADR) in Screening Colonoscopy: A RCT

Usual air insufflation during colonoscope insertion has been associated with possible missed cancers and precursor lesions in the proximal colon. Compared to usual air insufflations, chromoendoscopy with dye spray and the water method increase proximal colon adenoma detection rate (ADR) in patients undergoing screening colonoscopy. Dye spray is considered cumbersome. The water method is simple and easy-to-learn, albeit requires practice.

442 Technological Assistance of Cap-Assisted Chromoendoscopy Enhances the Detection Rates of Both Colorectal Adenoma and Proximal Serrated Polyp in an Average-Risk Screening Population: Preliminary Results of a Multi-Center Randomized Controlled Trial

Technological Assistance of Cap-Assisted Chromoendoscopy Enhances the Detection Rates of Both Colorectal Adenoma and Proximal Serrated Polyp in an Average-Risk Screening Population: Preliminary Results of a Multi-Center Randomized Controlled Trial Hyun-Soo Kim*, Hong Jun Park, Chan Sik Won, Hyo Keun Jeon, Dongil Park, Jae Myung Cha, Seun-Ja Park, Hwang Choi, Jeong Eun Shin, Chang Soo Eun, Jin-Oh Kim, Hyun Gun Kim, Seong-Eun Kim, Cheol Hee Park, Tae Il Kim, Sung Noh Hong, Dong-Hoon Yang, Byung Chang Kim, Byungho Nam Yonsei Univ. Wonju College of Medicine, Wonju, Republic of Korea; Sungkyunkwan University College of Medicine, Seoul, Republic of Korea; KyungHee University College of Medicine, Hanam, Republic of Korea; Kosin University College of Medicine, Busan, Republic of Korea; The Catholic University of Korea College of Medicine, Incheon, Republic of Korea; Dankook University College of Medicine, Cheonan, Republic of Korea; Hanyang University College of Medicine, Guri, Republic of Korea; Soonchunhyang University College of Medicine, Seoul, Republic of Korea; Ewha Womans University School of Medicine, Seoul, Republic of Korea; Hallym University College of Medicine, Anyang, Republic of Korea; Yonsei University College of Medicine, Seoul, Republic of Korea; Konkuk University School of Medicine, Seoul, Republic of Korea; University of Ulsan College of Medicine, Seoul, Republic of Korea; National Cancer Center, Goyang, Republic of Korea Background/Aim: There is growing evidence that a transparent cap or chromoendoscopy improve detection of colorectal polyps. However, the combined method of these two technologies has not been proven for colorectal polyp or adenoma detection rate. In this multicenter prospective randomized trial, we examined whether cap-assisted chromoendoscopy (CAP-ACE) enhances colorectal adenoma detection rate especially in the proximal colon. Methods: From March 2010 to October 2011, 1,202 asymptomatic average-risk subjects who underwent the first screening colonoscopy in an age of 45 to 75 were enrolled at 14 hospitals. Eighteen expert colonoscopists (more than 5,000 procedures) have performed procedures. Subjects were randomly allocated to CAP-ACE group and regular colonoscopy (RC) group. We prospectively compared insertion and withdrawal time, polyp detection rate (PDR), adenoma detection rate (ADR), and proximal serrated polyp detection rate (PSPDR) between the two groups. Results: A total of 1,202 subjects were enrolled; 598 CAP-ACEs and 604 RCs were performed. Overall PDR and ADR were 60.3% and 47.6%. A total of 52 advanced lesions were found including 16 tubulovillous adenomas, 2 villous adenomas, 13 high grade dysplasias, 11 intramucosal cancers and 10 invasive cancers. The time to cecal intubation (4.8 vs. 4.8 min, p 0.902) was not different between the groups but withdrawal time was prolonged in CAP-ACE group for indigocarmine solution spray and suction (10.5 vs. 8.7 min, p 0.001). Compared to RC, CAP-ACE did increase PDR (65.9% vs. 54.8%, p 0.001) and ADR (51.8% vs. 45.5%, p 0.033) significantly. In particular, this technological assistance of CAP-ACE even in experts significantly enhanced the proximal adenoma detection rate (34.8% vs. 28.8%, p 0.030) as well as PSPDR (10.5% vs. 6.1%, p 0.006). However, advanced lesions (CAPACE 26/598 (4.3%) vs. RC 26/604 (4.3%), p 0.99) including cancers were equally found between groups. Conclusion: Technological assistance of CAP-ACE enhances not only PDR but also ADR, especially in the proximal colon. These results suggest that CAP-ACE technology provide a potential solution for overcoming the limited effectiveness of colonoscopy in the proximal colon and should be considered as the preferred, high standard colorectal cancer screening method for the average-risk screening population.

Colonoscopy Quality Indicators Differ in the Proximal and Distal Colon

Purpose: Colonoscopy with polypectomy is associated with a reduction in colorectal cancer of the distal colon, but appears to be less protective for lesions of the proximal colon. The adenoma detection rate (ADR) is a validated measure of quality in colonoscopy. Polypectomy detection rate (PDR) has been proposed as a surrogate marker for ADR, demonstrating correlation with ADR in retrospective studies. The aim of this study was to evaluate PDR and ADR separately in the proximal and distal colon. Methods: We reviewed a colonoscopy database for outpatient procedures performed over a 6-month period by 20 gastroenterologists of a single academic medical center. Quality measures including ADR, PDR, mean adenomas per patient (MAP), mean polyps per patient (MPP) and advanced neoplasia detection rate (ANDR) were calculated. Procedures identifying 3 or more adenomas per patient (≥3DR) were also noted. The ratio of adenomas detected to polyps removed (adenoma/polyp ratio) was calculated. ADR and PDR were compared for lesions of the proximal versus distal colon (splenic flexure and below). Data were compared using the Chi-square test. Results: A total of 1921 colonoscopies were performed during the study period. ADR was 31% (13%-42%). ADR was significantly higher in men (36%) compared to women (26%), and in surveillance (47%) compared to screening studies (29%) (p < 0.001). PDR was 49% (16%-64%). PDR was significantly higher in men (63%) than in women (35%) (p < 0.001). The adenoma/polyp ratio was 0.49 (0.29-0.81). MAP was 0.58 (0.27-0.96) and MPP was 1.19 (0.27-1.71). Each measure was lower in the subset of screening colonoscopies (0.50 vs.0.58, p= 0.011 and 1.04 vs. 1.19, p< 0.001). ≥ 3DR was 5.4%, and ANDR was 6.7%. Colorectal cancer was detected in 10 patients (0.52%). In terms of distribution, 1038 polyps (corresponding to 753 adenomas) were removed from the proximal colon, and 1248 polyps (corresponding to 372 adenomas) were removed from the distal colon. Proximal PDR was significantly lower than distal PDR (26% vs. 32%, p= 0.05). Conversely, proximal ADR exceeded distal ADR overall (23% vs. 14%, p< 0.001) and in screening studies (19% vs. 14%; p = 0.016). Conclusion: Quality measures such as ADR and MAP varied amongst endoscopists. Higher ADR did not correlate with endoscopist's volume, patient gender, % surveillance, or withdrawal time. Adenoma/polyp ratio also varied, and PDR was not a consistent correlate of ADR in this study. The majority of adenomas were located in the proximal colon. Proximal polyps were more likely to be adenomas, compared with distal polyps. Proximal PDR may be a better surrogate marker compared with overall PDR for the detection of precancerous lesions of the colon.Table: Proximal and distal ADR and PDRTable: Table. Adenoma vs. polyp detection and other quality measures

The water method significantly enhances proximal diminutive adenoma detection rate in unsedated patients

BACKGROUND: Colonoscopy has been reported to fail to prevent some post screening colonoscopy incident cancers or minimize cancer mortality in the proximal colon. These reports question the effectiveness of colonoscopy in detecting all proximal adenomas. Diminutive ones which can be obscured by residual feces are particularly at risk. The water method provides salvage cleansing of sub-optimal preparations. OBJECTIVE: To test the hypothesis that the water method enhances proximal diminutive adenoma detection rate (ADR). DESIGN: The data bases of two parallel RCT were combined and analyzed. SETTING: Two Veterans Affairs endoscopy units. PATIENT AND METHODS: The water and air methods were compared in these two parallel RCT examining unsedated patients. MAIN OUTCOME MEASUREMENTS: The combined data on diminutive and overall ADR in the proximal colon, overall ADR, cecal intubation rate, withdrawal time and global bowel cleanliness score. RESULTS: Data in the water (n=92) and the air (n=90) groups were assessed. The water method yielded a significantly higher proximal diminutive ADR, 28.3% vs. 14.4% (p=0.0298); cecal intubation rate, 99% vs. 90% (p=0.0091); mean withdrawal time 19 (10) vs. 15 (8) min (p=0.0065) and mean global bowel cleanliness score during withdrawal, 2.6 (0.7) vs. 2.3 (0.6) (p=0.0032). Increase in proximal overall ADR in the water group approached significance, 29.3% vs. 16.7% (p=0.0592). LIMITATION: Small number of predominantly male veterans. CONCLUSION: The significantly higher cecal intubation rate, longer mean withdrawal time and better mean global bowel cleanliness score favor the outcome of significantly enhanced proximal diminutive ADR in the water group.

Water Infusion in Lieu of Air Insufflation and Suction Removal of Residual Air (Water Method) Significantly Increased Adenoma Detection Rate (ADR) in the Proximal Colon Based on Data Derived from Two RCT in U.S. Veterans

Purpose: Case-control reports suggested that colonoscopy failed to reduce incident cancers and cancer mortality in the right colon (Gastro 2004;127:452; AIM 2009;150:1; JNCI 2010;102:89). ADR, but not cecal intubation rate, was an independent predictor of the risk of interval colorectal cancer after screening colonoscopy (NEJM 2010; 362: 1795). The impact of high-definition, wide-angle endoscope (Gastro 2008; 135: 1062), narrow band imaging (Gastro 2009; 136: 410), dye-spray chromoendoscopy (Endoscopy 2006; 38: 444), withdrawal time >6 min (Gastro 2008; 135: 1892) or modifying bowel preparation (AJG doi:10.1038/ajg.2010.160) on ADR was inconclusive. A “colonoscopist-controlled” technique to obviate “missed” right-sided lesions is needed. The water method, albeit awkward, cumbersome and non conventional; but when executed “correctly” increases proximal ADR (GIE 2010; 71: AB248) merits consideration. The purpose of the report is to determine if the water method significantly increases proximal colon ADR in the results of two RCT with non-ADR-related primary outcomes. Methods: The water method was implemented by turning off the air pump prior to insertion of the colonoscope into the rectum. Residual air was suctioned to minimize angulations of flexures. Warm water was infused to assist in identification of the lumen. Residual fecal matter was aspirated before additional clean water was infused. Two RCT were conducted at two VA facilities to determine if the water method increased the proportion of patients who could complete colonoscopy without sedation when the option of scheduled, unsedated (N=82) or on demand sedation (N=100) was used. As part of the protocol overall ADR (proportion of patients with at least one adenoma) and ADR in the proximal colon were tracked in both RCT. Results: Randomization revealed balanced demographic and clinical variables. The water method yielded significantly higher ADR in the proximal colon. Conclusion: The data derived from two RCT revealed that the water method significantly increased ADR in the proximal colon. The results support the hypothesis that the “correct” use of the water method was associated with fewer “missed lesions” in the right colon. Assessment of its impact on interval colorectal cancer after screening colonoscopy deserves to be supported (Supported in part by ACG clinical research award).Table