Colonoscopy quality begins with a clean colon

Colorectal cancer (CRC) is the second most prevalent type of cancer in western countries, and almost half of people diagnosed with CRC die from the disease [1]. Colonoscopy and resection of adenomas are associated with a reduction in CRC incidence and mortality, although this protection is more obvious for cancers arising in the distal colon [2] [3] [4]. In an effort to further reduce CRC mortality, several indicators of quality have been defined to measure performance of colonoscopy and to target improvement in the quality of colonoscopy. These quality indicators include standard reporting and adequate levels for bowel preparation quality, withdrawal time, adenoma detection rate, burden for the patient, and complication rate [5] [6].

Of course, adequate bowel preparation is of utmost importance from the very beginning of the colonoscopy, to ensure safe intubation of the cecum and visualization of the colonic mucosa. Unfortunately, bowel preparation is adequate in only approximately 75 % of patients [7] [8] [9]. Impaired visualization of the mucosa can lead to missed lesions and an increase in the risk of interval carcinomas. In a large prospective multicenter European study, the detection of polyps of any size was dependent on cleansing quality [8]. In particular the detection of flat lesions, often harboring advanced histology, seems to be associated with adequate bowel preparation [9].

Poor preparation also leads to a longer procedure because of the time spent on washing, i. e., instilling and suctioning water [10]. Despite the time and effort expended by the endoscopist during colonoscopy to deal with poor bowel preparation, bowels that are very poorly prepared are often not rendered clean enough for adequate visualization. This leads to aborted colonoscopies that need rescheduling or a surveillance interval that is shorter than recommended by guidelines because the endoscopist lacks confidence in the examination [10]. Repeat colonoscopies are frustrating for both patients and endoscopists and increase colonoscopy costs by approximately 12 % – 22 % [10]. Therefore, continuous efforts are made to reduce the burden of bowel cleansing for the patient, to ensure an adequate quality of colonoscopy.

In this issue of Endoscopy, 2 studies on a novel system for bowel cleansing during colonoscopy (JetPrep) are published [11] [12] . This system is composed of a disposable catheter device with a nozzle at the tip that is inserted through the working channel of a standard colonoscope. It is connected to an irrigation unit with a predefined pressure and flow rate, creating a wide funnel-shaped jet of water that could facilitate colon cleansing. Both small studies show similar results.

The Belgian and Israeli researchers performed a prospective, single-centre study reporting on safety and efficacy of this new device. Upon cecal intubation, patients with imperfect bowel preparation were randomly allocated to either the JetPrep group or the group that received standard care with syringe irrigation to clean the colon during withdrawal. Indeed, “blinding” for the type of bowel cleansing was impossible. The cleansing efficacy was evaluated using a segmental scoring scale, rating the bowel preparation quality (ranging from 1 (excellent) to 4 (poor)) in each colonic segment before and after irrigation. In the Belgian study, 42 patients were included because upon cecal intubation because bowel preparation was indeed insufficient. [11] The JetPrep system was superior to standard care for cleansing results, with a mean improvement in the grade of the bowel cleansing quality (Boston Bowel Prep Scale) of 0.99 and 0.55 respectively. When looking at the efficacy per colonic segment, results were statistically significant for the proximal colon only. [11] Although not powered for these endpoints, the duration of the procedure and the rate of polyp detection were similar between the groups and no clinical complications occurred, except for some red streaks on the mucosa in 2 patients. In the study by Eliakim et al, 38 patients were included and also here the JetPrep cleansing group had a greater improvement in overall bowel cleanliness than the standard group: 0.74 vs 0.19, again being statistically different in the cecum and ascending colon only. [12] Also in this study no differences in procedure time and adverse effects were encountered.

Both authors conclude that the JetPrep device could be a solution for patients that turn out to have a poor bowel preparation during colonoscopy. This outcome could be of interest to the readers of Endoscopy, as imperfectly clean colons are daily practice. The JetPrep system can be mounted on the colonoscope at any moment in case bowel preparation appears insufficient during endoscopy. Despite the fact that the catheter device impairs the simultaneous use of other devices through the working channel, procedure time was not prolonged in this small study.

However, from the colon prep scales at baseline as well as the fact that the cecum was reached in all cases, it can be concluded that bowel preparation was only moderately and not severely impaired in the patients included in this study. This seems of importance as aspiration is done through the regular suction channel of the endoscope and thus it will be impossible to suction large residuals like fibres and seeds. Therefore, the group of patients that might benefit of this system seems rather small.

Our main concern, however, is the effort the endoscopist has to take to clean the bowel. When much time and effort is spent on cleaning before inspection can even be commenced, this might result in a reduced motivation of the endoscopist. Instead of spending the time allocated for colonoscopy by cleansing the colon, we think that endoscopists should take their time to search the colon thoroughly for neoplastic lesions and use their skills to remove them radically.

Several patient characteristics predict poor bowel preparation, like decreased bowel motility, hospitalized patients, elderly patients, and patients that previously had suboptimal bowel preparation [13]. Identifying these persons gives the opportunity to give them extra care and personal advice. Besides these predictors, the quality of the preparation largely depends on the compliance and motivation of the patient. The ingestion of a high volume of polyethylene glycol (PEG) solution is challenging and is often described by the patient as being a greater burden than the colonoscopy procedure itself. [13] [14] [15]. Studies evaluating predictors of poor preparation showed that 18 % of the people failed to follow preparation instructions, and most probably this figure is higher because it is “socially undesirable” to report failure for a patient. [13] Clear instructions on bowel preparation and explanation of the importance of adequate cleansing are essential. Understanding the importance of a successful bowel preparation to cancer prevention enhances patients’ acceptance and compliance, and improves the quality of the bowel preparation. [15] When all these preventive measures to obtain a good bowel preparation have failed, the JetPrep system might have an additional value to the armentarium of the endoscopist. Larger randomized studies are warranted to demonstrate the effect of the JetPrep system on all important quality parameters of colonoscopy.

• References

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