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Advantages of low dose polyethylene glycol + ascorbate split-dose colonoscopy preparation for colorectal screening
Caterina Palmonari, Nicolò Landini, Chiara Zanforlin, Michela Borghesi, Viviana Cifalà, Claudio Gregorio, Alessandro Pezzoli, Admena Rreshketa, Chiara Chiericati
Caterina Palmonari, Nicolò Landini, Chiara Zanforlin, Chiara Chiericati, AUSL-U.O.C. Oncological Screenings, Local Health Agency of Ferrara, Ferrara 44121, Emilia-Romagna, Italy
Michela Borghesi, Department of Economics and Management, University of Ferrara, Ferrara 44121, Emilia-Romagna, Italy
Viviana Cifalà, Gastroenterology Unit, S. Anna University Hospital, Ferrara 44124, Emilia-Romagna, Italy
Claudio Gregorio, General Surgery Unit, S. Anna University Hospital, Ferrara 44124, Emilia-Romagna, Italy
Alessandro Pezzoli, Gastroenterology Unit, ULSS 5 Polesana, Rovigo 45100, Veneto, Italy
Admena Rreshketa, Unit of Biostatistics, Epidemiology, and Public Health, Department of Cardiac, Thoracic, and Vascular Sciences, University of Padova, Padova 35131, Veneto, Italy
Author contributions: Palmonari C was responsible for funding acquisition; Palmonari C and Landini N were responsible for conceptualization, project administration, and supervision; Palmonari C, Landini N, Zanforlin C, and Chiericati C were responsible for validation; Palmonari C, Landini N, Cifalà V, Gregorio C, Pezzoli A, and Rreshketa A were responsible for methodology; Cifalà V, Gregorio C, and Pezzoli A were responsible for resources; Landini N was responsible for visualization; Landini N, Zanforlin C, and Chiericati C were responsible for data curation and investigation; Landini N and Borghesi M were responsible for formal analysis and writing original draft; Palmonari C, Landini N, Zanforlin C, Borghesi M, Cifalà V, Gregorio C, Pezzoli A, Rreshketa A, and Chiericati C were responsible for writing review and editing; all of the authors read and approved the final version of the manuscript to be published.
Conflict-of-interest statement: All authors declare no conflict of interest in publishing the manuscript.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Corresponding author: Nicolò Landini, Post Doctoral Researcher, AUSL-U.O.C. Oncological Screenings, Local Health Agency of Ferrara, Corso Della Giovecca 203, Ferrara 44121, Emilia-Romagna, Italy.
nicolo.landini@unife.it
Received: December 15, 2025
Revised: February 3, 2026
Accepted: April 14, 2026
Published online: July 15, 2026
Processing time: 206 Days and 14.1 Hours
BACKGROUND
Colorectal cancer is the third occurring neoplasm type worldwide, with approximately two million people cases in 2020. Hence, activation of accurate screening and diagnostic protocols within the population is crucial for its prevention, contributing to public health improvement along with healthcare costs containment. Colonoscopy represents the gold standard for lesion detection, yet remains an invasive and distressful procedure, also due requiring appropriate intestinal prep through ingestion of laxative concoctions. For the Italian National Health System, this preparation is administered as 4-liter of polyethylene glycol (PEG), split in two rounds, which often results in insufficient bowel cleanliness to perform colonoscopy.
AIM
To implement a less distressful and more efficient preparation for colonoscopy preparation, to improve bowel cleansing.
METHODS
After obtaining the permission from the local National Health System management in 2022, 1-liter of PEG (1L-PEG) and ascorbate (ASC) was administered to patients as colonoscopy preparation, instead of the usual 4-liter of PEG.
RESULTS
The 1L-PEG + ASC gave improved results at the end of 2023, with 96.33% of acceptable cleansing among the screened population, of which 63.56% resulting in Optimal cleaning level for the Boston Scale. The colonoscopy adherence from patients increased in the period observed from 78.30% to 85.20%.
CONCLUSION
Implementing 1L-PEG + ASC gave better results than other preparations and diminished patient distress, leading to an increase in the operative colonoscopies percentage, and positively influencing the adherence to the screening protocol.
Core Tip: The 1-liter of polyethylene glycol and ascorbate was introduced to enhance colonoscopy preparation from the standard (4-liter of polyethylene glycol, distressful for patients due to the volume and not operatively optimal due to poor bowel cleansing). Results from pilot study (426 patients) showed above 90% of the patients with adequate bowel cleansing (Boston Scale value ≥ 6). Provincial screening results from 2022 to 2023 after the renewed protocol resulted in 96.33% of the population having adequate bowel cleansing for colonoscopy, with 63.56% showing optimal cleaning. Patients’ compliance increased of +5.30% for 1st and +3.90% for 2nd level screening protocols.
