Background:

Colorectal cancer is the most frequent neoplasm and the second cause of cancer death in Spain. Colon cleansing is critical for visualization of lesions at colonoscopy. High-quality cleansing allows for correct detection and resection of all lesions and may contribute to adequate risk stratification and follow-up interval.

Low-volume laxatives improve tolerance of the colonoscopy preparation without reducing its effectiveness. Currently, the most widely used low-volume laxatives are one liter of Polyethylene glycol + ascorbate (PEG1A) and sodium picosulfate + magnesium citrate (PSCM).

The evidence on the comparison of laxatives to achieve a high-quality colonic cleansing is very scarce.

Hypothesis:

Polyethylene glycol 1 liter with ascorbate is superior to sodium picosulfate and magnesium citrate in high-quality colon cleansing.

Objective:

Overall objective:

To compare the global high-quality cleansing frequency between the two laxatives using the Harefield Scale (HS).

The primary objective is to demonstrate non-inferiority in global high-quality cleansing of PEG1A compared to PSCM. If non-inferiority is demonstrated, superiority of PEG1A will be analyzed.

Specific objectives:

• Frequency of global high-quality cleansing using the Boston Bowel Preparation Scale (BBPS).
• Frequency of adequate-quality cleansing using the HS and BBPS scales.
• Tolerance and adverse effects of both laxatives.
• Detection of lesions, total adenomas, advanced adenomas, total serrated lesions, advanced serrated lesions and colorectal cancer.
• Detection of neoplastic lesions in the different colon segments (proximal, transverse, descending, sigmoid and rectum).
• Association between detected lesions and the quality of the preparation, according to the HS and BBPS scales.

Methods:

Phase 4, multi-centric, randomized, single-blind (endoscopist), parallel study with two treatment arms: PEG1A (Pleinvue®) and PSCM (Citrafleet®).

This study will be performed in 1104 patients with a scheduled colonoscopy for any indication, who need a bowel preparation for the colonoscopy.

Subjects will be randomly assigned to 1 of 2 treatment groups with a 1:1 allocation using block sizes of 6 cases in each center. The treatment assignment will be open to the participant and the physician. The investigator who performs the colonoscopy and assesses the primary outcome (digestive endoscopist) will be blinded.

In both treatment groups, participants will receive instructions about colonoscopy preparation. Laxative treatment (PEG1A/PSCM) will be administered in two doses, at 9 pm on the day before intervention and 5 hours before colonoscopy, on an outpatient basis.

The day of the colonoscopy appointment will be the final visit of the study. The participant will be asked through a questionnaire about adherence to instructions, tolerance and acceptability to the preparation, and the appearance of side effects. No follow-up period is considered after intervention.

Inclusion Criteria:

• Outpatients with previously scheduled colonoscopy with any indication: screening, follow-up, or symptoms.

Exclusion Criteria:

• Age less than 18 years or more than 85 years
• Hospital admission at the time of colonoscopy
• Partial or total colectomy
• Severe constipation
• Active inflammatory bowel disease
• Severe kidney or liver failure
• Pregnancy or lactation
• Inability to understand the instructions by language barrier or cognitive disorder
• Refusal to participate in the study.

The assignment of each treatment will be displayed at the time of patient enrollment and will be open to the participant and the physician. The investigator who performs the colonoscopy and assesses the primary outcome (digestive endoscopist) is blinded.