Evolving techniques in colonoscopy

Quality metrics of screening colonoscopies performed by PAs

BACKGROUND

Many communities face a shortage of qualified endoscopists. Training physician assistants (PAs) to perform colonoscopies can expand the availability of colorectal cancer screening. This study examined screening colonoscopy metrics and quality indicators among gastroenterologists, supervised PAs, and gastroenterology fellows.

METHODS

Consecutive patients undergoing average-risk screening colonoscopy were stratified into one of three groups by endoscopist type. Procedure and pathology reports were reviewed for the technical performance and quality metrics of the providers.

RESULTS

PAs performed comparably to gastroenterologists in technical performance and quality metrics, and demonstrated higher cecal intubation rates than their gastroenterologist colleagues. Comparisons of attending physicians and PAs grouped by years of experience also did not show notable differences in performance.

CONCLUSIONS

In a supervised practice, PAs performed on par with their gastroenterology colleagues on established colonoscopy quality indicators. Following proper training, PAs can be employed in the provision of screening colonoscopy.

The advantages of water immersion colonoscopy in ambulatory service

BACKGROUND/AIMS

The purpose of this prospective study was to compare patients' discomfort during water immersion (WI) colonoscopy without sedation or available on request, with that of patients during air insufflation (AI) colonoscopy with sedation, in the ambulatory setting.

MATERIAL AND METHODS

A prospective observational study was conducted in 100 patients who performed a colonoscopy between August 2015 and February 2016 in an Ambulatory Gastroenterology Center in Cluj-Napoca, Romania. They were divided into two branches A and B. Patients in Group A underwent a classic colonoscopy with AI and standard sedation (2 mg of midazolam and 50 mg of tramadol), while patients in Group B underwent an unsedated or on demand sedation colonoscopy with WI technique.

RESULTS

The patients in group A presented a higher discomfort (statistically significant) compared to those in group B, and had also the median total discomfort score higher than those in group B. The patients in group A had also a higher discomfort score after examination. The total time of examination was the same in the two groups, but in group B the progression to cecum time was 3 minutes lower than for those in group A. A greater discomfort of the patient was correlated with the longer time required to reach the cecum.

CONCLUSION

In conclusion, WI colonoscopy is superior to AI technique in reducing insertion pain, progression-to-cecum time, minimizing sedation requirements and also in the willingness to repeat the technique.

A prospective randomised study comparing double-balloon colonoscopy and conventional colonoscopy in pre-defined technically difficult cases

BACKGROUNDS AND AIM

Technically 'difficult' (TD) colonoscopy is associated with incomplete colonoscopy, discomfort and longer procedures. Double-balloon colonoscopy (DBC) may facilitate TD colonoscopy. The primary outcome was to compare the time taken to achieve caecal intubation during conventional colonoscopy (CC) and DBC in patient with a TD colon.

METHODS

We performed a prospective, randomised study comparing DBC and CC for TD colonoscopy. Patients were screened for parameters predictive of TD colonoscopy using an original scoring system and randomised to DBC or CC. Pain, sedation dose, colonoscopy completeness, time taken for cecal intubation, procedure completion, recovery time and patient satisfaction were recorded.

RESULTS

Forty-four patients were recruited (DBC=22; CC=22). DBC facilitated total colonoscopy in 22 cases whereas 9 CC procedures were incomplete (P=0.019). Median pre-procedure difficulty scores were equal for both groups (4.0 vs. 4.0). Mean patient discomfort, pain scores and recovery time were significantly lower for the DBC group (2.3 vs. 5.5, P=0.001; 2.0 vs. 5.9, P=0.005; 5 vs. 20min, P=0.014 respectively). Mean time taken for cecal intubation was similar (17.5 vs. 14min, P=0.18); CONCLUSION: DBC facilitates colonoscopy completion and may be a more comfortable alternative to CC for TD cases although the time taken to achieve caecal intubation was similar.

Ultrathin versus pediatric instruments for colonoscopy in older female patients: A randomized trial

BACKGROUND AND AIM

Small-caliber endoscopes such as gastroscopes or pediatric colonoscopes are occasionally required to negotiate fixed or angulated colons. However, the use of a new ultrathin instrument (diameter 7.0 mm) narrower than other conventional colonoscopes has not been evaluated. The aim of the present study was to compare the use compare the use of an ultrathin colonoscope (UTC) with a pediatric colonoscope (PDC) for colonoscopy in older female patients.

METHODS

A prospective, randomized, controlled trial was conducted in a single academic endoscopy unit. A total of 77 female patients aged ≥70 years undergoing unsedated colonoscopy were randomized to colonoscopy with a UTC (n = 39) or PDC (n = 38). Primary outcome measurement was the degree of pain using a numerical rating scale, and secondary outcomes were cecal intubation rate, ileal intubation rate, time to cecum and adenoma detection rate.

RESULTS

There was a significant difference in reported pain using the numerical rating scale (median, UTC 1 vs PDC 4, P < 0.0001). Cecal intubation rates were 97.4% in UTC and 92.1% in PDC (P = 0.36), and ileal intubation rates were 82.0% and 89.4% (P = 0.76), respectively. However, median times to cecum were significantly longer using UTC compared with PDC (15.2 min vs 11.1 min, P = 0.022). Adenoma detection rates were 30.7% in UTC and 26.3% in PDC (P = 0.80).

CONCLUSIONS

Colonoscopy using UTC was almost equivalent to that of PDC in older female patients, with significantly less pain compared with PDC. UTC may be an alternative to PDC for the difficult colon.

Current state of micro-robots/devices as substitutes for screening colonoscopy: assessment based on technology readiness levels

BACKGROUND

Previous reports have described several candidates, which have the potential to replace colonoscopy, but to date, there is still no device capable of fully replacing flexible colonoscopy in the management of colonic disorders and for mass adult population screening for asymptomatic colorectal cancer.

MATERIALS AND METHODS

NASA developed the TRL methodology to describe and define the stages of development before use and marketing of any device. The definitions of the TRLS used in the present review are those formulated by "The US Department of Defense Technology Readiness Assessment Guidance" but adapted to micro-robots for colonoscopy. All the devices included are reported in scientific literature. They were identified by a systematic search in Web of Science, PubMed and IEEE Xplore amongst other sources. Devices that clearly lack the potential for full replacement of flexible colonoscopy were excluded.

ASSESSMENT OF THE CURRENT SITUATION

The technological salient features of all the devices included for assessment are described briefly, with particular focus on device propulsion. The devices are classified according to the TRL criteria based on the reported information. An analysis is next undertaken of the characteristics and salient features of the devices included in the review: wireless/tethered devices, data storage-transmission and navigation, additional functionality, residual technology challenges and clinical and socio-economical needs.

CONCLUSIONS

Few devices currently possess the required functionality and performance to replace the conventional colonoscopy. The requirements, including functionalities which favour the development of a micro-robot platform to replace colonoscopy, are highlighted.

Quality monitoring in colonoscopy: Time to act

Colonoscopy is the gold standard test for colorectal cancer screening. The primary advantage of colonoscopy as opposed to other screening modalities is the ability to provide therapy by removal of precancerous lesions at the time of detection. However, colonoscopy may miss clinically important neoplastic polyps. The value of colonoscopy in reducing incidence of colorectal cancer is dependent on many factors including, the patient, provider, and facility level. A high quality examination includes adequate bowel preparation, optimal colonoscopy technique, meticulous inspection during withdrawal, identification of subtle flat lesions, and complete polypectomy. Considerable variation among institutions and endoscopists has been reported in the literature. In attempt to diminish this disparity, various approaches have been advocated to improve the quality of colonoscopy. The overall impact of these interventions is not yet well defined. Implementing optimal education and training and subsequently analyzing the impact of these endeavors in improvement of quality will be essential to augment the utility of colonoscopy for the prevention of colorectal cancer.

How can screening colonoscopy be optimized?

Since the implementation of screening programmes, both the incidence and mortality of colorectal cancer have been decreasing. The choice of the preferred screening tool, however, is divergent and the adherence to screening programmes in most countries is still low. Cancer detection tests such as the guaiac faecal occult blood test (gFOBT) and the immunohistochemical FOBT (iFOBT) achieve higher acceptance than endoscopy. The sensitivity and specificity of iFOBT are higher than those of gFOBT, but gFOBT is cheaper and easier to perform. Endoscopic screening, which represents cancer prevention tests, has higher sensitivity for premalignant lesions than gFOBT and iFOBT and enables diagnosis and therapy in one single procedure. Since screening colonoscopy and sigmoidoscopy are invasive procedures with potentially severe adverse events, the highest possible quality must be provided. High-tech equipment, experience, training, quality control programmes, excellent bowel preparation and low adverse event rates are pivotal. Alternative screening tools such as CT colonography, barium enema CT and multitarget stool DNA tests have not been established as routine screening tools to date.

Diagnostic yield of third eye retroscope on adenoma detection during colonoscopy: A systematic review and meta-analysis

AIM: To determine the diagnostic yield of the “third eye retroscope”, on adenoma detection rate during screening colonoscopy.

METHODS: The “third eye retroscope” when used with standard colonoscopy provides an additional retrograde view to visualize lesions on the proximal aspects of folds and flexures. We searched MEDLINE (PubMed and Ovid), SCOPUS (including MEDLINE and EMBASE databases), Cochrane Database of Systemic Reviews, Google Scholar, and CINAHL Plus databases to identify studies that evaluated diagnostic yield of “third eye retroscope” during screening colonoscopy. DerSimonian Laird random effects model was used to generate the overall effect for each outcome. We evaluated statistical heterogeneity among the studies by using the Cochran Q statistic and quantified by I² statistics.

RESULTS: Four distinct studies with a total of 920 patients, mean age 59.83 (95%CI: 56.77-62.83) years, were included in the review. The additional adenoma detection rate (AADR) defined as the number of additional adenomas identified due to “third eye retroscope” device in comparison to standard colonoscopy alone was 19.9% (95%CI: 7.3-43.9). AADR for right and left colon were 13.9% (95%CI: 9.4-20) and 10.7 (95%CI: 1.9-42), respectively. AADR for polyps ≥ 6 mm and ≥ 10 mm were 24.6% (95%CI: 16.6-34.9) and 24.2% (95%CI: 12.9-40.8), respectively. The additional polyp detection rate defined as the number of additional polyps identified due to “third eye retroscope” device in comparison to standard colonoscopy alone was 19.8% (95%CI: 7.9-41.8). There were no complications reported with use of “third eye retroscope” device.

CONCLUSION: The “third eye retroscope” device when used with standard colonoscopy is safe and detects 19.9% additional adenomas, compared to standard colonoscopy alone.

Endoscopists with low adenoma detection rates benefit from high-definition endoscopy

BACKGROUND

An endoscopists adenoma detection rate (ADR) of less than 20 % correlates with high risk for occurrence of interval cancer. The impact of high-definition (HD) imaging on the ADR is discussed controversially. We aimed to investigate whether detection rates of individual endoscopists increase within 1 year before and 1 year after the switch from standard to HD endoscopy.

METHODS

This cohort study analyzed 6,330 screening colonoscopies (2,968 with standard and 3,362 with HD) performed by 42 endoscopists between November 2007 and March 2013 within a nationwide quality assurance program for screening colonoscopy.

RESULTS

The ADR of endoscopists with a low ADR (<20 %) increased significantly higher (from 11.8 to 18.1 %, p = 0.003) than of those with a high ADR (≥ 20 %) (from 28.6 to 30.7 %, p = 0.439) after switch from standard to HD colonoscopes (p = 0.0076). The proportion of endoscopists with an ADR < 20 % decreased from 45 to 42.9 % (p = 0.593). There was no significant increase in age- and sex-adjusted detection rates of adenomas (20.2 vs 23.7 %; p = 0.089), advanced adenomas (4.7 vs 5.5 %; p = 0.479), flat adenomas (2.7 vs 3.1 %; p = 0.515), polyps (38.8 vs 41.5 %; p = 0.305), proximal polyps (18.5 vs 20 %; p = 0.469) and hyperplastic polyps (15 vs 17.2 %; p = 0.243) of endoscopists after switch to HD colonoscopes. There was no difference in detection rates of flat polyps (5.5 vs 5.5 %; p = 0.987).

CONCLUSIONS

The use of HD scopes is associated with marginal improvement in adenoma detection rates limited to those endoscopists with low adenoma detection rates prior to its introduction.

Optical diagnosis of colorectal polyps using high-definition i-scan: An educational experience

AIM: To examine performances regarding prediction of polyp histology using high-definition (HD) i-scan in a group of endoscopists with varying levels of experience.

METHODS: We used a digital library of HD i-scan still images, comprising twin pictures (surface enhancement and tone enhancement), collected at our university hospital. We defined endoscopic features of adenomatous and non-adenomatous polyps, according to the following parameters: color, surface pattern and vascular pattern. We familiarized the participating endoscopists on optical diagnosis of colorectal polyps using a 20-min didactic training session. All endoscopists were asked to evaluate an image set of 50 colorectal polyps with regard to polyp histology. We classified the diagnoses into high confidence (i.e., cases in which the endoscopist could assign a diagnosis with certainty) and low confidence diagnoses (i.e., cases in which the endoscopist preferred to send the polyp for formal histology). Mean sensitivity, specificity and accuracy per endoscopist/image were computed and differences between groups tested using independent-samples t tests. High vs low confidence diagnoses were compared using the paired-samples t test.

RESULTS: Eleven endoscopists without previous experience on optical diagnosis evaluated a total of 550 images (396 adenomatous, 154 non-adenomatous). Mean sensitivity, specificity and accuracy for diagnosing adenomas were 79.3%, 85.7% and 81.1%, respectively. No significant differences were found between gastroenterologists and trainees regarding performances of optical diagnosis (mean accuracy 78.0% vs 82.9%, P = 0.098). Diminutive lesions were predicted with a lower mean accuracy as compared to non-diminutive lesions (74.2% vs 93.1%, P = 0.008). A total of 446 (81.1%) diagnoses were made with high confidence. High confidence diagnoses corresponded to a significantly higher mean accuracy than low confidence diagnoses (84.0% vs 64.3%, P = 0.008). A total of 319 (58.0%) images were evaluated as having excellent quality. Considering excellent quality images in conjunction with high confidence diagnosis, overall accuracy increased to 92.8%.

CONCLUSION: After a single training session, endoscopists with varying levels of experience can already provide optical diagnosis with an accuracy of 84.0%.

Benefits and limitations of cap-fitted colonoscopy in screening colonoscopy

BACKGROUND

Colonoscopy is widely used to detect colorectal cancer and to remove precancerous lesions to reduce the risk of colonic cancer.

AIMS

To examine the benefits and limitations of cap-fitted colonoscopy compared to conventional colonoscopy in terms of technical performance and colorectal adenoma detection rate.

METHODS

Screening colonoscopies performed from 2009 to 2010 with or without a transparent cap were retrospectively examined to compare the rate of successful intubation, cecal intubation time, and number, size, shape, and location of adenomas detected. An inclusion criterion was visualization of >95 % of the right colon.

RESULTS

Data from 2,301 colonoscopies (1,165 with cap-fitted colonoscopy, 1,136 without the transparent cap) were retrospectively analyzed. Procedures were performed by four experienced endoscopists. The subjects' demographic characteristics and technical performances were similar between the two methods. The only significant difference in the technical performance between the two techniques was a shorter cecal intubation time with cap-fitted colonoscopy (5.3 vs. 6.6 min; p = 0.045) by one endoscopist. The total number of adenomas detected was significantly higher with cap-fitted colonoscopy than without the cap (586 vs. 484, respectively; p < 0.0001). Adenoma detection with cap-fitted endoscopy was significantly higher in the right colon than in the left colon (19 vs. 12 %, respectively; p = 0.0001).

CONCLUSION

Cap-fitted colonoscopy did not improve the technical aspects of colonoscopy but significantly increased adenoma detection, especially in the right colon. It did not increase the detection rate of flat or depressed adenomas.

Water-aided colonoscopy: a systematic review

BACKGROUND

Water-aided methods for colonoscopy are distinguished by the timing of removal of infused water, predominantly during withdrawal (water immersion) or during insertion (water exchange).

OBJECTIVE

To discuss the impact of these approaches on colonoscopy pain and adenoma detection rate (ADR).

DESIGN

Systematic review.

SETTING

Randomized, controlled trial (RCT) that compared water-aided methods and air insufflation during colonoscope insertion.

PATIENTS

Patients undergoing colonoscopy.

INTERVENTION

Medline, PubMed, and Google searches (January 2008-December 2011) and personal communications of manuscripts in press were considered to identify appropriate RCTs.

MAIN OUTCOME MEASUREMENTS

Pain during colonoscopy and ADR. RCTs were grouped according to whether water immersion or water exchange was used. Reported pain scores and ADR were tabulated based on group assignment.

RESULTS

Pain during colonoscopy is significantly reduced by both water immersion and water exchange compared with traditional air insufflation. The reduction in pain scores was qualitatively greater with water exchange as compared with water immersion. A mixed pattern of increases and decreases in ADR was observed with water immersion. A higher ADR, especially proximal to the splenic flexure, was obtained when water exchange was implemented.

LIMITATIONS

Differences in the reports limit application of meta-analysis. The inability to blind the colonoscopists exposed the observations to uncertain bias.

CONCLUSION

Compared with air insufflation, both water immersion and water exchange significantly reduce colonoscopy pain. Water exchange may be superior to water immersion in minimizing colonoscopy discomfort and in increasing ADR. A head-to-head comparison of these 3 approaches is required.

Progress and challenges in colorectal cancer screening

Although faecal and endoscopic tests appear to be effective in reducing colorectal cancer incidence and mortality, further technological and organizational advances are expected to improve the performance and acceptability of these tests. Several attempts to improve endoscopic technology have been made in order to improve the detection rate of neoplasia, especially in the proximal colon. Based on the latest evidence on the long-term efficacy of screening tests, new strategies including endoscopic and faecal modalities have also been proposed in order to improve participation and the diagnostic yield of programmatic screening. Overall, several factors in terms of both efficacy and costs of screening strategies, including the high cost of biological therapy for advanced colorectal cancer, are likely to affect the cost-effectiveness of CRC screening in the future.