Colon cleansing regimens. A clinical study in 1200 patients

Progress of colorectal cancer screening in United States: Past achievements and future challenges

The United States has seen progress with colorectal cancer with both falling incidence and mortality rates. Factoring into this decline, the significance of early detection and removal of precancerous lesions through screening must be underscored. With the advancement of screening modalities, attention has been directed towards optimizing the quality of screening and detecting adenomas. Colorectal cancer screening has been a major agenda item for national gastroenterology societies, culminating in a major victory with passage of the Balanced Budget Act that allowed for Medicare coverage of colorectal cancer screening. Colonoscopy as the primary screening modality was solidified in the 1990s after landmark studies demonstrated its superiority over modalities for detecting precancerous polyps. Despite progress, colorectal cancer screening disparities between race and gender continue to exist. Legislative efforts are on-going and include the SCREEN Act and Dent Act that aim to further improve access to screening. The National Colorectal Cancer Roundtable has launched colorectal cancer screening initiatives targeting at risk populations. Today, the current goal of these initiatives is to reach colorectal screening rate of 80% of eligible patients by 2018. With these initiatives, efforts to narrow the gaps in screening disparities and lower overall mortality have been prioritized and continued by the medical community. This review article details colorectal cancer screening progress to date and highlights major studies and initiatives that have solidified its success in the United States.

The Cleansing Enema

The effects of the ‘tap-water enemas till clear’ method of bowel cleansing on the technical quality of double-contrast enema (DCE) were studied in 123 outpatients referred for DCE. Patients with one or two tap-water enemas (1.75 litres) before the DCE had significantly more faecal residue and flocculation of contrast medium than patients with three or more enemas. However, the number of enemas did not correlate significantly with mucosal coating. The results suggest that at least three tap-water enemas should be given before DCE.

History, evolution, and current status of radiologic imaging tests for colorectal cancer screening

Colorectal cancer screening is thought to be an effective tool with which to reduce the mortality from colorectal cancer through early detection and removal of colonic adenomas and early colon cancers. In this article, we review the history, evolution, and current status of imaging tests of the colon-including single-contrast barium enema, double-contrast barium enema, computed tomographic (CT) colonography, and magnetic resonance (MR) colonography-for colorectal cancer screening. Despite its documented value in the detection of colonic polyps, the double-contrast barium enema has largely disappeared as a screening test because it is widely perceived as a labor-intensive, time-consuming, and technically demanding procedure. In the past decade, the barium enema has been supplanted by CT colonography as the major imaging test in colorectal cancer screening in the United States, with MR colonography emerging as another viable option in Europe. Although MR colonography does not require ionizing radiation, the radiation dose for CT colonography has decreased substantially, and regular screening with this technique has a high benefit-to-risk ratio. In recent years, CT colonography has been validated as an effective tool for use in colorectal cancer screening that is increasingly being disseminated.

Pharmacokinetics of Caffeine following a Single Administration of Coffee Enema versus Oral Coffee Consumption in Healthy Male Subjects

The objective of this study was to determine the pharmacokinetics of caffeine after single administration of a coffee enema versus coffee consumed orally in healthy male subjects. The study design was an open-label, randomized two-phase crossover study. Eleven healthy subjects were randomly assigned either to receive 500 mL of coffee enema for 10 minutes or to consume 180 mL of ready-to-drink coffee beverage. After a washout period of at least 10 days, all the subjects were switched to receive the alternate coffee procedure. Blood samples were collected immediately before and at specific time points until 12 hours after coffee administration in each phase. The mean caffeine content in both the coffee solution prepared for the coffee enema and the ready-to-drink coffee beverage was not statistically different. The C_max and AUC of caffeine obtained from the coffee enema were about 3.5 times significantly less than those of the coffee consumed orally, despite having slightly but statistically faster T_max. The t_1/2 of caffeine obtained following both coffee procedures did not statistically differ. In summary, the relative bioavailability of caffeine obtained from the coffee enema was about 3.5 times significantly less than those of the coffee consumed orally.

Antioxidant effects after coffee enema or oral coffee consumption in healthy Thai male volunteers

We designed an open-label, randomized two-phase crossover study to investigate the antioxidant effects after single and multiple doses of a coffee enema versus coffee consumed orally. Eleven healthy subjects were randomly assigned to either receive a coffee enema (3 times weekly for 6 visits) or consume ready-to-drink coffee (2 times daily for 11 days). After a washout period, subjects were switched to receive the alternate coffee procedure. Blood samples were collected at specific time points for the determination of serum levels of glutathione (GSH), malondialdehyde (MDA) and trolox equivalent antioxidant capacity (TEAC). The findings showed that either single or multiple administrations of the coffee enema or orally consumed coffee doses seemed not to produce any beneficial effects to enhance serum GSH levels or to decrease serum MDA levels over the study period of 12 days. In contrast, mean serum TEAC levels at day 12 after the coffee enema and at days 6 and 12 after oral coffee consumption were significantly reduced from their corresponding baseline values. Thus, no beneficial effects with respect to an enhancement of serum GSH and TEAC levels or a decrease in serum MDA concentrations were demonstrated after coffee enema or orally consumed ready-to-drink coffee.

Bioavailability of glycyrrhizin from Shaoyao-Gancao-Tang in laxative-treated rats

Shaoyao-Gancao-Tang (SGT), a traditional Chinese formulation composed of Shaoyao (Paeoniae Radix) and Gancao (Glycyrrhizae Radix), is frequently used in conjunction with laxatives such as sodium picosulfate in colonoscopy to relieve abdominal pains. We have investigated the alterations of the bioavailability of glycyrrhizin when SGT was co-administered with sodium picosulfate and we tried to identify a regimen that might minimize the alterations. Glycyrrhizin is one of the active glycosides in Gancao and SGT and is hydrolysed into the bioactive metabolite, 18β-glycyrrhetic acid (GA) by intestinal bacteria following oral administration. We found that the maximum plasma concentration (Cmax) and the area under the mean concentration vs time curve from zero to 24 h (AUC0–24 h) of GA from a single dose of SGT administered 5 h after a single pretreatment with sodium picosulfate were significantly reduced to 15% and 20% of the control level in rats, respectively. These reductions were still significant four days after sodium picosulfate pretreatment, but were restored by repetitive administration of SGT following sodium picosulfate pretreatment. Similar reductions and recovery were observed for the glycyrrhizin-metabolizing activity of intestinal bacteria in rat faeces. The results warrant clinical studies for co-administration of laxatives such as sodium picosulfate and SGT.

Interaction between Shaoyao-Gancao-Tang and a laxative with respect to alteration of paeoniflorin metabolism by intestinal bacteria in rats

Shaoyao-Gancao-Tang (SGT), a traditional Chinese herbal medicine (Kampo formulation) containing Shaoyao (Paeoniae Radix) and Gancao (Glycyrrhizae Radix), is co-administered with laxative sodium picosulfate as a premedication for relieving the pain accompanying colonoscopy. Paeoniflorin (PF), an active glycoside of SGT, is metabolized into the antispasmodic agent paeonimetabolin-I (PM-I) by intestinal bacteria after oral administration. The objective of the present study was to investigate whether the co-administered laxative (sodium picosulfate) influences the metabolism of PF to PM-I by intestinal bacteria. We found that the PF-metabolizing activity of intestinal bacteria in rat feces was significantly reduced to approximately 34% of initial levels by a single sodium picosulfate pretreatment and took approximately 6 days to recover. Repeated administration of SGT after the sodium picosulfate pretreatment significantly shortened the recovery period to around 2 days. Similar results were also observed for plasma PM-I concentration. Since PM-I has muscle relaxant activity, the present results suggest that repetitive administration of SGT after sodium picosulfate pretreatment might be useful to relieve the pain associated with colonoscopy.

Double-contrast barium enema technique

During a double-contrast barium enema the radiologist interacts with the patient, the controls of the fluoroscope, and the image on the television monitor. The radiologist paints an image of the colon; the barium is the paint, the colon is the canvas. The radiologist manipulates the barium pool, the air column, and the patient to create images. Although the radiologist may have a plan going into the examination, the game plan is altered by the patient's ability to tolerate and perform the study, the length of the colon, and pathology encountered. If the radiologist understands the goals to be achieved, the studied can be tailored to fit what is happening in the fluoroscopic suite.

Double-contrast barium enema examination technique

This review article presents the principles for performing a safe, comfortable, and accurate double-contrast barium enema examination. The procedure is a flexible examination in which the fluoroscopist interacts with the patient, the controls of the fluoroscope, and the image on the television monitor. During a double-contrast examination, images of the colon are created by manipulating the patient, the barium pool, and the amount of air insufflated into the rectum. Fluoroscopy is essential for guiding the radiologist to obtain spot images with adequate technical factors. The fluoroscopist analyzes the luminal contour, the barium-coated mucosal surface en face, and the barium pool to detect abnormalities in the colon. With careful technique, a high-quality examination can be performed in most patients.

Bowel preparation for the double-contrast barium enema: how to maintain coating with cleansing?

AIM

Poor mucosal coating, due to excess of fluid in the colon lumen, is a problem when the oral lavage method (4 litres of an iso-osmotic saline solution containing polyethylene glycol) is used as a preparation for double-contrast barium enema. Our aim was to assess the value of prior administration of sennosides to obtain a clean colon with a reduced volume of polyethylene glycol (PEG)-saline solution, but maintaining good mucosal coating.

MATERIALS AND METHODS

After a 2-day low-residue diet, three different oral preparations were compared: (i) 4 litres of a PEG-saline solution (SELG) and 15 mg of bisacodyl (116 patients, SELG-4 group); (ii) 156 mg of sennosides, 15 g of magnesium sulphate, and 2 litres of water (116 patients, SennMg group); (iii) 156mg of sennosides and 2 litres of SELG (116 patients, SennSELG group). Compliance, complaints, cleansing, mucosal coating, and fluid retention were evaluated.

RESULTS

Compliance was > 94% in every group. A higher percentage of mild nausea was observed in SELG-4 group, of mild abdominal cramping in SennMg group, of substantial abdominal cramping in SennSELG group (P < 0.02). Cleansing was better in SennSELG than in both the SELG-4 (P = 0.0003) and SennMg (P = 0.0353) group. Mucosal coating was better in SennMg than both SELG-4 (P = 0.0034) and SennSELG (P < 0.0001) group. There was more residual fluid in the SennSELG group than both in SELG-4 (P = 0.0029) and SennMg (P = 0.0059) group.

CONCLUSION

For colon cleansing, the combination of sennosides and PEG-saline solution was better than either the 4 litre PEG protocol or the combination of sennosides and magnesium sulphate. For mucosal coating, the protocol combining sennosides and magnesium sulphate was more effective than either protocols using the PEG-saline solution. This may be due to the interaction of residual magnesium ions in the colon lumen with the barium suspension.

Comparison of two bowel preparations for colonoscopy: sodium picosulphate with magnesium citrate versus sulphate-free polyethylene glycol lavage solution

OBJECTIVES

Adequate preparation of the bowel is essential for accurate colonoscopic examination. We compared colonic preparation with sodium picosulphate plus magnesium citrate (SPS-Mg) with sulphate-free polyethylene glycol electrolyte lavage (PEG-EL) solution before colonoscopy, for quality of bowel cleansing, patient discomfort, and side effects.

METHODS

Sixty-eight consecutive patients were randomly assigned to receive either 3 sachets of SPS-Mg (16.5 g each) (n = 39) or 3 L of PEG-EL (n = 29) on the day before colonoscopy. Shortly before the procedure each patient was interviewed to determine the degree of discomfort (1 = none or mild, 2 = moderate, 3 = severe) and side effects. The quality of bowel cleansing was graded by a gastroenterologist who was unaware of the method of preparation (from 1 = poor to 4 = excellent).

RESULTS

Of the 29 PEG-EL patients, four (14%) did not complete the preparation because of side effects. The degree of discomfort was significantly greater with PEG-EL (mean score, 2.3 +/- 0.7) than with SPS-Mg (mean score, 1.4 +/- 0.5; p < 0.01). Nausea and vomiting were significantly more common in the PEG-EL group (38% vs 13%; p < 0.05). Using intention-to-treat analysis, bowel cleansing proved to be significantly better with SPS-Mg than with PEG-EL (mean score +/- SD, 3.05 +/- 0.9 and 2.57 +/- 1.0, respectively; p = 0.036).

CONCLUSIONS

Colonic preparation with SPS-Mg is better tolerated, associated with significantly fewer side effects, and results in higher quality bowel cleansing than preparation with PEG-EL.

A blinded clinical trial comparing conventional cleansing enema, Pico-salax and Golytely for barium enema bowel preparation

An evaluator-blinded randomized clinical trial was undertaken to assess the effectiveness and patient acceptance of three bowel cleansing regimens: conventional cleansing enema, Pico-salax and Golytely.

PATIENTS AND METHODS

One hundred and fifty patients, referred for barium enema examination, were allocated to one of the three regimens. Both the radiographers and the radiologists did not know the method of preparation. Radiographers were requested to enter the patients' data, the number of bowel openings, the patients' comments of the preparation and side effects. Films were reviewed independently by two experienced radiologists for the degree of bowel cleanliness and quality of barium coating.

RESULTS

The mean (standard deviation) of bowel opening frequency for the cleansing enema, Pico-Salax and Golytely were 3.6(4.4), 8.3(4.8) and 7.1(4.2), respectively, with less bowel opening in the cleansing enema. There was less nausea associated with the cleansing enema (P = 0.006), more vomiting with Golytely (P = 0.008), less abdominal fullness with Pico-salax (P = 0.0006), less anorectal irritation with Golytely (P = 0.025), and no difference in the abdominal pain amongst three groups. There was no statistically significant difference in the number of bowel openings between the groups. Patients found that Pico-salax tasted better than Golytely (P = 0.0094) and Golytely was less accepted in the amount of fluid intake (P = 0.0018 and P < 0.0002 comparing Golytely with the cleansing enema and Pico-salax). Chi-squared testing showed no statistically significant difference in bowel cleanliness and quality of barium coating among the three preparations.

CONCLUSIONS

There was no difference in the effectiveness of the three regimens. Pico-salax seems the most acceptable because it has the fewest side effects.

Preparation of the colon for double-contrast barium enema: comparison of Picolax, Picolax with cleansing enema and Citramag (2 sachets)--a randomized prospective trial

A randomized prospective trial was undertaken on 196 consecutive patients referred for double-contrast barium enema examination to assess the relative efficacy of three colon cleansing regimes: Citramag (2 sachets), Picolax and Picolax with a preliminary cleansing enema. Each of the regimes was preceded by a 5 day low residue diet. The radiographs from the examinations were assessed on a double-blind basis. The quality of bowel preparation was significantly poorer (P < 0.001) in the group receiving the preliminary cleansing enema, notably with respect to mucosal coating, compared with the other two groups. The quality of the preparation was slightly better in the group receiving Picolax alone than in the Citramag group (P < 0.01), the difference being most apparent in the proximal colon. The laxatives were equally well tolerated. The study has formed the basis of a departmental audit. As a result, the bowel preparation has been standardized to a 5 day period of dietary restriction followed by 2 Picolax sachets. This measure has improved efficiency within the department with no sacrifice in quality.

Determining the minimal interval between cleansing water enema and double-contrast barium enema examination

In a prospective study 59 consecutive outpatients having double-contrast barium enemas (DCBE) were randomised into four groups. Each group had their enema performed at either a 15, 30, 45 or 60 minute interval following the end of a 1.5 litre cleansing water enema. Review of the films by two radiologists demonstrated that adequate mucosal coating was obtained after 45 minutes. The DCBE should therefore be performed at a minimum time interval of 45 minutes following colonic lavage, and not beforehand.

Dietary fibers in the preparation of the bowel for diagnostic barium enema

The effect on colon cleanness of adding dietary fiber or placebo to a standard bowel preparation scheme before diagnostic barium enemas was tested in a randomized, double-blind study including 120 consecutive outpatients admitted for diagnostic barium enemas. Colon cleanness was scored as satisfactory, intermediate, or unsatisfactory. No case of unsatisfactory cleansing appeared in the group given fiber. Mean score was slightly better in the fiber group but the difference was not statistically significant. Dietary fiber does not have a negative effect on colon cleansing but may instead have a beneficial effect, which is possibly more pronounced in patients with constipation.

Intraoperative high-flow antegrade irrigation. A new bowel-cleansing system

A new intraoperative method, employing a specially designed apparatus, is described by which the colon can be cleansed to a degree not obtainable by other methods. The method enables continuous antegrade irrigation with large volumes of irrigant at high rates of flow, prior to enterotomy. It has been tested in an experimental canine model and found to be safe and effective.

Washout versus non-washout (Picolax) preparation for double-contrast barium enemas

A non-washout preparation using Picolax in 40 patients, compared with a standard method using washouts in 38 patients, showed no significant difference in the contamination by residual formed or semiliquid faeces, although Picolax was associated with significantly more contamination due to adherent faeces and mucus. The overall differences in contamination were most marked in the transverse colon. Picolax also affected the smooth muscle tone of the bowel wall, causing an increase in 'mucosal crinkling'.

Reliability of routine double-contrast examination (DCE) of the large bowel in polyp detection: a prospective clinical study

A total of 2,118 consecutive patients, examined with double-contrast examination of the large bowel (DCE), were evaluated radiographically, clinically, and endoscopically for up to 48 months. A total of 402 polyps were diagnosed during the follow-up period. Of these, 307 were revealed at the first DCE and 95 at subsequent endoscopy or autopsy. The accuracy of the DCE for demonstrating or excluding patients with polypoid lesions of the colon was 97%, whereas the predictive value of a positive DCE report was 96% and a negative one, 97%. However, the ability to demonstrate every known polyp at DCE was only 63%, although the probability of a polypoid lesion demonstrated at DCE being a true polyp was 92%.