Introduction

Adequate bowel preparation is paramount for a high-quality screening colonoscopy. Despite the importance of adequate bowel preparation, there is a lack of large studies that associated the degree of bowel preparation with long-term colorectal cancer outcomes in screening patients.

Aims & Methods

In a large population-based screening program database in Austria, quality of bowel preparation was estimated according to the Aronchick scale by the endoscopist (excellent, good, fair, poor and inadequate bowel preparation). We used logistic regression to assess the influence of bowel preparation on the detection of different polyp types and the inter-physician variation in bowel preparation scoring. Time to event analyses were performed to investigate the association of bowel preparation with post-colonoscopy colorectal cancer (PCCRC) death.

Results

335466 colonoscopies between 01/2012 and follow-up until 12/2022 were eligible for the analyses. As compared to excellent bowel preparation, adenoma detection was not significantly lower for good bowel preparation (OR 1.01, 95% CI 0.9971 - 1.0329, p = 0.1023), however, adenoma detection was significantly lower in fair bowel preparation (OR 0.97, 95% CI 0.9408 - 0.9939, p = 0.0166). Individuals who had fair or lower bowel preparation at screening colonoscopy had significantly higher hazards for PCCRC death (HR for fair bowel preparation 2.56, 95% CI 1.67 - 3.94, p <0.001).

Conclusion

Fair bowel preparation on the Aronchick scale was not only associated with a lower adenoma detection probability, but also with increased risk for PCCRC death. Efforts should be made to increase bowel cleansing above fair scores.

Disclosure

MT had advised for Abbvie, Albireo, BiomX, Boehringer Ingelheim, Falk, Gilead, Genfit, Hightide, Intercept, Jannsen, MSD, Novartis, Phenex, Pliant, Regulus, Siemens, Shire, has received grants / research support from Albireo, Alnylam, Cymabay, Falk Pharma, Gilead, Intercept, MSD, Takeda, UltraGenyx, had received speakersfees form BMS, Falk Foundation, Gilead, Intercept, Madrigal, MSD, Roche, has received travel grants from AbbVie, Falk Foundation, Gilead, Intercept, Janssen, Roche, the Medical Universities of Graz and Vienna have filed patents on medical use of norUDCA and is listed as co-inventor.
All other authors have no conflict of interest to declare.

Introduction

Previous studies showed that adhering to high-quality screening colonoscopy leads to markedly decreased incidence and mortality of colorectal cancer. However, more is needed to know about the impact of the duration of participation on quality parameters.

Aims & Methods

This study aims to evaluate the relationship between the duration of endoscopists' participation within the Austrian quality assurance program for screening colonoscopy and their quality parameters. A generalized linear mixed model, adjusted for sex and age, was utilized to evaluate the effect of the time elapsed since participation on quality parameters, such as adenoma detection rate (ADR), advanced adenoma detection rate (AADR) and carcinoma detection rate (CDR).

Results

392 endoscopists provided data from 326,445 screening colonoscopies from 2007 to 2022. Results showed that each year of participation in the quality assurance initiative led to a 1.02% increase in ADR (95% CI [1.004-1.034], p-value = 0.013) as well as a 1.17% increase in CDR (95% CI [1.107-1.245], p-value <0.001) adjusted for patients' age and sex. The advanced adenoma detection rate increased by 1.00% each year of participation (95% CI [0.983-1.023], p-value = 0.762).

Conclusion

The participation of endoscopists in the quality assurance initiative was associated with a significant increase in ADR and CDR for each year of participation. However, the increase in AADR was not statistically significant.

Introduction

Adequate bowel preparation is a well-established quality parameter for screening colonoscopies correlating with another important quality parameter of colonoscopy, the adenoma detection rate (ADR). Additional parameters like sessile serrated adenoma detection rate (SSADR) and advanced adenoma detection rate (AADR) have been discussed as additional quality indicators without a clear correlation with bowel preparation quality.

Aims & Methods

In this study we aimed to compare ADR, AADR and SSADR between different bowel preparation qualities in a large real-world colorectal cancer screening cohort.
Colonoscopy data from the Austrian national colorectal cancer screening program collected between 2012 and 2022 were analysed. Bowel preparation was categorized into five different groups (excellent, good, fair, poor and insufficient) according to the Aronchik Scale. ADR, SSADR and AADR were calculated for each group.

Results

A total of 375,352 colonoscopies (48.2 % in men) performed by 404 endoscopists working in hospitals and private practices were included in the final analysis. The cecal intubation rate (CIR) was ≥90% in adequate bowel preparations and also in insufficient bowel preparations. However, CIR in poor bowel preparations was only 57.3%. The most common reasons for incomplete colonoscopy in these patients, as stated by the treating endoscopist, was extensive fecal contamination in 93.2% of cases. Mean overall ADR, SSADR and AADR were 23.8%, 8.5% and 4.2%, respectively. ADR/SSADR/AADR in excellent, good, fair, poor and insufficient bowel preparations were 26.9%/10.1%/3.1%, 27.2/8.5%/3.3%, 27.2/8.5%/3.3%, 15.3/9.2%/7.3% and 22,5/6.4%/4%, respectively. In patients with insufficient bowel preparation exclusively in the right colon, ADR/SSADR and AADR were 25.9%/4.9% and 3.1%.

Conclusion

The recommended international standard of an ADR ≥25% was achieved in patients with adequate (excellent, good and fair) bowel preparations. Interestingly, the CIR in poor bowel preparations was very low (57.3%) even compared with the CIR in insufficient bowel preparations (89.9%). Further, detection of advanced adenomas was not inferior in the inadequate bowel preparation groups, suggesting that these types of adenomas might be also seen without an adequate bowel preparation.

Introduction

Use of sedation is associated with a positive effect on endoscopists ADR and a higher proportion of colonoscopies with a withdrawal time > 10. However, the impact of sedation on the risk of post colonoscopy colorectal cancer (PCCRC)deaths remains unclear.

Aims & Methods

Retrospective cohort study within a large population based screening program database in Austria, the association of sedation in screening colonoscopy with post-colonoscopy colorectal cancer death was analysed. Logistic regression was used to estimate the effect of sedation on PCCRC-death.

Results

407.598 screening colonoscopies were analyzed. In 371.132 (91,1%) sedation was used. 46.8% of sedated patients were men compared to 68,2% in unsedated patients (HR 1.94 (1.60, 2.35), p<0,001). Coecum was reached in 97.3% of sedated and 95.5% of unsedated individuals. (HR 4.22 (3.06, 5.82) p<0,001).
Cumulative incidence of PCCRC in sedated individuals was 0.05 (95% CI 0.05-0.5) after 4 years, 0.07% (0.07-0.07) after 6 years, 0.11% (0.11-0.11) after 8 years, 0.14 (0.14-0.14) after 10 years, 0.18% (0.18-0.18) after 12 years. In unsedated patient, cumulative incidence was 0.1% (0-1-0-1) after 4 years, 0.15% (0.15-0.15) after 6 years, 0.22% (0.21-0.23) after 8 years, 0.25% (0.24-0.26%) after 10 years, 0.27% (0.26-0.28) after 12 years. Hazard ratio was 1.31 (0.94-1.83, p=0.1) for sedation in PCCRC-deaths.

Conclusion

Incidence of PCCRC-death was higher in unsedated patients, however this effect was not significant and probably an effect of lower cecal intubation rate within unsedated patients.

Introduction

Aims & Methods

Results

Conclusion

Introduction

Screening colonoscopy is effective in preventing colorectal cancer by removing precancerous lesions. Incomplete examinations are associated with a higher risk of post-colonoscopy colorectal cancer. Therefore, the minimum standard for cecal intubation rate is >90%, and the target standard >95%. However, little is known about the distribution of reasons for incomplete colonoscopy in colorectal cancer screening programs.

Aims & Methods

Based on data from the Austrian quality assurance program for screening colonoscopy, we analyzed the reasons for incomplete colonoscopies. We further investigated whether the use of sedation and the adenoma detection rate (ADR) are associated with lower rates of complete examination.

Results

489,800 screening colonoscopies were analyzed within the Austrian quality assurance program. Of these, 2.9% (n=14,325) were incomplete. 59,7% of those patients were female and 40.3% male. 85.4% of patients with an incomplete vs. 91.2% with a complete examination were sedated (p<0.001). The reasons for not reaching the cecum were insufficient bowel preparation in 23.3% (n=3335), pain in 23% (n=3291), stenosis in 11.7% (n=1674), complications in 1.6% (n=227), and other factors in 40.5% (n=5798). 69% of incomplete colonoscopies were performed by endoscopists with an ADR lower than 25% and 31% with an ADR over 25%. 54.6% of complete examinations were done by endoscopists with an ADR lower than 25% and 45.4% with an ADR over 25% (p<0.001).

Conclusion

The target standard of the cecal intubation rate has been achieved (97.1%). Incomplete colonoscopies were more often in female (84.4%) compared to male (40.3%), performed in unsedated patients and by endoscopists with an ADR <25%. The most common reason for not reaching the cecum was categorized as other factors (40.5%), this category is not well defined and requires further investigation.

Introduction

The diagnostic accuracy of colorectal cancer (CRC) screening via colonoscopy is influenced by the quality of bowel preparation. The adenoma detection rate is another well-known quality measure for CRC screening colonoscopies. Counting the total number of adenomas identified during each colonoscopy can provide a more comprehensive assessment of the procedure's effectiveness. Adenomas that are 1 cm or larger, exhibit high-grade dysplasia, or have a villous architecture are considered advanced adenomas and carry a higher risk of progressing to adenocarcinoma.

Aims & Methods

The aims of our study were to assess whether there was an association between the adequacy of bowel preparation and both adenoma detection rate and the advanced adenoma detection rate, and to investigate whether there was a correlation between the quality of preparation and the number of adenomas detected per colonoscopy. We present a retrospective, single-center study of complete screening colonoscopies performed on patients with 50 years old or more, over 18 months (from April 2022 to September 2023), and their respective histological reports. Adequate preparation was considered if all colonic segments scored 2 or more points on the Boston Bowel Preparation Scale (BBPS). Statistical analysis was conducted using SPSS v29.0.

Results

672 total colonoscopies were analyzed. The average age was 64.5 ± 8.0 years, and there was no predominance between genders. BBPS scores ranged from 0 to 9. The majority of patients had adequate bowel preparation (74%, n = 502), with BBPS scores of 6, 7, 8, and 9 in 37.7%, 7.0%, 22.9%, and 7% of cases, respectively. The adenoma detection rate was 41.2% and the detection rate of advanced adenomas was 16.4%. The number of adenomas detected per colonoscopy ranged from 0 to 11 adenomas. No association was found between having adequate preparation and having at least 1 adenoma (p>0.05) or having at least 1 advanced adenoma (p>0.05). There was no statistically significant difference in the average number of adenomas per colonoscopy between patients with and without adequate preparation (p>0.05). There was no correlation between the BBPS score and the number of adenomas per colonoscopy (p>0.05).

Conclusion

The detection rates of adenomas and advanced adenomas were not associated with the adequacy of bowel preparation. No correlation was found between the quality of preparation and the number of adenomas per colonoscopy. Despite the need to repeat another colonoscopy with adequate BBPS for optimal observation of the mucosa, concluding screening procedures in patients with inadequate bowel preparation has still proven to be useful. As long as it is considered safe, endoscopists should be encouraged to conclude all screening procedures.