Randomised and Controlled Clinical Trial of Polyethylene Glycol with Electrolytes and Ascorbic Acid in Comparison to Sodium Phosphate for Bowel Preparation Before Colon Cancer Screening Colonoscopy

Abstract

Introduction: The effectiveness of endoscopic screening for colon cancer depends on good bowel preparation to ensure complete (100%) mucosal visualization. The safety and acceptability of the bowel preparation are of key importance for screening colonoscopies. Aims & Methods: To compare the efficacy, safety and acceptability of bowel preparation with low-volume polyethylene glycol plus electrolytes and ascorbic acid (PEG + Asc, MoviPrep) or sodium phosphate (NaP, Fleet Phospho-soda) in adults undergoing elective colonoscopy for colon cancer screening. Consenting participants were randomized to take either PEG+Asc (n = 242) or NaP (n = 114). PEG + Asc was taken the evening before and the morning of the colonoscopy (total 2 litres), NaP was taken in the morning and evening before the procedure. The primary endpoint was the success of bowel cleansing rated from videotapes by a panel of endoscopists unaware of treatment allocations. Successful cleansing was defined as complete visualization (Grade 2-4 on a scale of 0-4) in all segments. Patients' views about the preparations were also elicited. Adverse events were recorded. Results: The rate of successful bowel cleansing (i.e. complete visualization in all segments) according to the expert raters was significantly higher with PEG + Asc (93.4% [95% CI 89.5 to 96.1]) than with NaP (22.8% [15.5 to 31.6%] p < 0.001). The main difference in cleansing success was in the ascending colon. The proportion of unsuccessful cleansing (Grade 0 or 1) for PEG+Asc and NaP respectively in each segment was: rectum 2%, 18%; sigmoid colon 4%, 26%; descending colon 2%, 24%; transverse colon 3%, 28%; ascending colon 3%, 69%. The acceptability ratings for the preparations were similar (mean visual analogue scores (VAS) ranging from 0 = ‘excellent’ to 100 = ‘very bad’ were 24.4 for PEG + Asc and 28.2 for NaP, p = 0.238). Taste ratings for PEG + Asc were significantly better than for NaP (mean VAS 31.2 and 38.1 respectively, p = 0.011). The proportion of patients prepared to receive the same preparation again was significantly higher in the PEG + Asc group (88% vs 78% p < 0.001). Both preparations were well tolerated. No serious, treatment-related adverse events were reported. Conclusion: PEG + Asc provided superior bowel cleansing to NaP and was better tolerated. Excellent 100% mucosal visualization combined with improved patient acceptability and a good safety profile mean that the 2L PEG + Asc preparation is an ideal bowel preparation for colon cancer screening.