In the western world there are approximately 1.4 million new cases of colon cancer each year. An estimated 550,000 deaths occur worldwide from colon cancer annually.1 Despite a high incidence of this malignancy, it is relatively preventable when compared with other cancers. This is largely because most cases of this disease have a long phase of premaligancy. Colon cancer screening initiatives, such as those in the United States and the United Kingdom have targeted the removal of adenomatous lesions of the colon to reduce the incidence of colon cancer. The mainstay of this strategy is the use of colonoscopy. Indeed, colonoscopy is an invaluable weapon for this battle; however, its use has not been fully perfected to date. In addition to optimizing colonoscopy for the endoscopist, issues still remain for patients in reference to tolerance of the bowel prep, quality of life, and lost productivity at work. All these factors can be improved upon going forward. The hopeful result will be that everybody wins.
Several studies have concluded that the adenoma detection rate (ADR) at colonoscopy is effected by the quality of the bowel prep.2,3 Lebwohl and colleagues found that suboptimal bowel prep resulted in a miss rate for advanced adenoma of 27% and a miss rate for all adenomas of 42% (as compared with 22% in pooled data from previous studies). Harewood and colleagues concluded that an inadequate prep resulted in a lower ADR. In this study, ADR with an inadequate prep was significantly lower for lesions <1 cm diameter. For larger lesions, in this study, ADR was not altered by inadequate prep. Certainly these studies emphasize the importance of adequate colonoscopy preparation. A suboptimal prep can reduce the accuracy of colonoscopy and as a result blunt its ability to protect patients from colon cancer. In addition, an inadequate prep increases cost to the healthcare system by reducing intervals between examinations. An infrequently discussed indirect cost associated with reduced interval between examinations is decreased labor productivity for the patient (and possibly the patient's ride).
The ideal method for performing colonoscopy prep has evolved over the years. Some have concluded that “no single bowel prep emerges as consistently superior.”4 Nonetheless, the quest to optimize prep and the subsequent colonoscopy have continued. Traditionally, all patients were prepped over the 24 to 48 hours before the procedure. In these protocols, minimal prepping was done on the day of the procedure. It has only been within the past decade that the distinction has been made between preps for morning and afternoon procedures. The first major change to the traditional colonoscopy prep came with the advent of the split dose prep (SDP). With these regimens half of the prep is taken in the morning of the examination. Published studies have shown promising results for this strategy.5–7 Studies by Marmo and colleagues, Park and colleagues, and El Sayed and colleagues showed that SDP with polyethylene glycol solutions were superior to the standard large volume prep taken the day before. One advantage of the SDP is the potential for the patient to experience less sleep disruption. Aoun et al8 concluded that patients undergoing SDP were able to avoid dietary restrictions during their prep with no adverse effect on prep quality, patient tolerability, or side effects. As a result of these studies many have concluded colonoscopy should be performed within a short time frame from the last liquid consumed. Several authors have enthusiastically stated that colonoscopy should be performed no later than 8 hours after the conclusion of the SDP.5,6,9,10 After this time frame it has been observed that the prep in the right colon starts to deteriorate.10 This is thought to be from postlavage stool entering the proximal colon. A number of studies have shown the benefit of taking the whole prep in the morning of a scheduled afternoon colonoscopy, whereas another demonstrates that morning only and SDP yield equal results.11–13 Proponents of the morning only prep point to the benefit of no sleep disruption and less effect on work with this strategy. The distinction between morning colonoscopy and afternoon colonoscopy has been made clearer by studies, which demonstrate differences in efficacy. Higher failure rates have been observed in afternoon colonoscopies, possibly secondary to factors such as endoscopist fatigue or deteriorating bowel preps.14 Parra-Blanco et al and Sanaka et al have shown that ADR is reduced in afternoon colonoscopy when compared with morning examinations.15,16 It has also been observed that performance of a same day prep improved ADR for afternoon procedures.16
This is the background for this edition's study by Bhanmdari and Longcroft-Wheaton.17 This group endeavored upon a single-blind prospective cohort study comparing SDP and same day prep with sodium picosulphate for patients undergoing afternoon colonoscopy. The study concluded that the same day bowel prep was more effective than the SDP. In addition, the same day prep garnered higher quality of life and patient satisfaction scores. Bhanmdari and Longcroft-Wheaton have built upon the existing knowledge in this area by demonstrating that findings of others using polyethylene glycol preps are translatable to other formulations. Certainly this will tempt other researchers to expand this concept to a wider array of prep formulations, which can be delivered in the morning of a procedure. This study further delineates the different approaches required for morning and afternoon colonoscopy. In the future, it is unlikely that the “one prep fits all” model will persist. It seems that momentum is gaining to recommend SDP for morning examinations and same day prep for afternoon examinations. Bhanmdari and Longcroft-Wheaton have added to this momentum with their study. Quality-of-life considerations are not trivial when it comes to promoting the use of colonoscopy. As important as the quoted studies are, patient-driven factors are probably of equal importance. “Word of mouth” experiences between patients will go a long way in determining the dissemination of colonoscopy in the future. It is estimated that over 30 million colonoscopies are done annually worldwide for screening alone. This massive number has staggering implications when it comes to lost labor productivity. The promotion of same day preps such as the one studies group and others could potentially save millions of lost work days for patients as compared with the traditional day before prep. In these uncertain times many patients do not want to miss work (and possibly put their jobs at risk) for a screening examination. The same day prep for afternoon colonoscopy model will be especially appealing to this group of patients. It seems that same day prep for afternoon colonoscopy is a viable option to offer our patients. It provides a high-quality prep for the endoscopist; it improves the patient's quality of life as compared with other regimens, and most likely results in less time lost from work. It would seem that everybody wins!
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