Introduction

EMR remains the primary therapeutic option for LNPCP in western practice, but new procedures and techniques are increasingly employed. Large published series previously defined expected rates of, and risk factors for, residual/recurrent adenoma after endoscopic resection (ER). However, these may no longer be relevant.

Aims & Methods

We aimed to identify independent risk factors for recurrent/residual adenoma in a contemporary cohort of LNPCP treated by ER compared to a historical cohort. Patients with LNPCP treated by ER at a tertiary referral centre between January 2011 and September 2023 who had completed 6 month surveillance (SC1) were included. Patients were divided into contemporary (January 2018 – September 2023) and historical (January 2011 – December 2017) cohorts. Post-ER scars were examined using with magnification chromoendoscopy and NBI/BLI. Clinicopathological features significantly associated with recurrent/residual adenoma on univariate analysis were subjected to multiple logistic regression to identify independent risk factors.

Results

1517 ER were performed over the study period of which 946 met the inclusion criteria and had undergone SC1: 483 in the contemporary cohort and 463 in the historical cohort. In the contemporary cohort 313 (65%) were treated using ESD compared to 117 (25%) in the historical cohort (p<0.001). En bloc resection was more frequently achieved in the contemporary cohort compared to the historical cohort (70% versus 33%, p<0.001). Recurrent/residual adenoma at SC1 was detected in 2.5% in the contemporary cohort compared to 8.9% in the historical cohort (p<0.001). For the historical cohort, multivariate analysis revealed that previous failed attempt at resection (OR 2.80, 95% CI 1.14-6.88, p=0.02); piecemeal resection (OR 5.21, 95% CI 1.18-23.02, p=0.03) and involvement of >75% of the circumference of the lumen (OR 5.80, 95% CI 2.07-16.25, p<0.001) were independently associated with recurrent/residual adenoma: However, for the contemporary cohort, only difficult access to the lesion (OR 4.24, 95% CI 1.21-14.78) was independently associated with recurrent residual adenoma at SC1.

Conclusion

Significant changes have taken place in ER practice over the last decade. This study demonstrates this has led to a marked alteration in previously established expected outcomes and risk factors for recurrence. Furthermore, the increasing use of adjunctive measures and techniques such as ESD throughout the colorectum may help drive down recurrence rates with the advantage of producing high quality histopathological specimens and accurate diagnosis, leading to a reduction in surveillance requirements. These data should help define performance standards for advanced resection units as well as guide informed consent and decision making for patients.

Introduction

Computer-aided detection (CADe) systems have gained attention for their use in colonoscopy, with growing evidence of increased adenoma detection rates (ADR). However, results remain inconsistent, and debate regarding their usefulness continues, including their impact on serrated lesion (SL) detection and performance across varying levels of endoscopist expertise. Given that CADe is used as a real-time assistive tool, it is crucial to confirm its efficacy in lesion detection before considering long-term outcomes.

Aims & Methods

We conducted a multinational, multicenter randomized controlled trial in the Asia-Pacific (Project CAD/NCCH2217; jRCT1032230396) to assess the efficacy of CADe in improving lesion detection during colonoscopy performed as part of colorectal cancer (CRC) screening [1]. We enrolled asymptomatic individuals aged 50–79 years undergoing either primary screening colonoscopy or colonoscopy following a positive fecal immunochemical test (FIT), who had not received colonoscopy in the past 5 years. Participants were randomly assigned (1:1) to the CADe group (colonoscopy with CADe assistance) or the standard group (colonoscopy without CADe) using a minimization method to balance age, sex, colonoscopy indication, endoscopist experience, and country/region. In the CADe group, approved CADe devices were used in accordance with each country's regulations, including EndoBRAIN-EYE, ENDO-AID, CAD EYE, and WISE VISION. All procedures were performed by endoscopists with experience of ≥500 colonoscopies. The primary endpoint was adenoma detection rate (ADR). Secondary endpoints included adenomas per colonoscopy (APC), advanced ADR (AADR), sessile serrated lesion detection rate (SSLDR), sessile serrated lesions per colonoscopy (SSLPC), scope withdrawal time, and the resection rate of non-neoplastic lesions. Planned sample size was 1400 cases (one-sided α = 0.05, 80% power).

Results

Of the 1,399 participants enrolled between December 28, 2023, and March 6, 2025, 1,373 were included in the full analysis set (688 and 685 in the CADe and standard groups, respectively). In both groups, the proportions of primary screening and post-FIT colonoscopies were 75% and 25%, respectively. No differences were observed between the CADe and standard groups in ADR (54.7% vs. 53.9%; odds ratio [OR] 1.04; 95% confidence interval [CI], 0.83–1.30, one-sided p=0.38), APC (1.17 vs. 1.24; risk ratio [RR], 0.94; 95% CI, 0.81–1.09), or AADR (5.5% vs. 7.6%; OR, 0.71; 95% CI, 0.46–1.10). The CADe group showed higher SSLDR (9.0% vs. 6.0%; OR, 1.55; 95% CI, 1.03–2.33) and SSLPC (0.11 vs. 0.07; RR, 1.65; 95% CI, 1.09–2.50). Subgroup analysis based on endoscopist experience demonstrated a higher SSLDR in the CADe group among those with 500–4,999 (10.1% vs. 5.4%) and 5,000–9,999 (11.9% vs. 3.6%) prior colonoscopies, but not among those with experience of ≥10,000 procedures (7.0% vs. 7.5%). There was no difference between groups in the non-neoplastic lesion resection rate (14.7% vs. 13.4%; OR, 1.11; 95% CI, 0.82–1.50), and the median scope withdrawal time in cases without polypectomy was 9 minutes in both groups.

Conclusion

CADe assistance did not improve adenoma detection where high ADR was already achieved with standard colonoscopy. Nevertheless, it enhanced SSL detection, except among highly experienced endoscopists, without prolonging withdrawal time or increasing unnecessary polypectomies. While our findings do not overstate the efficacy of CADe, they support a reasonable and practical role for its use in improving colonoscopy quality in CRC screening.

References

1. Sekiguchi M, et al. Protocol for a multicenter randomized controlled trial to assess the usefulness of computer-aided detection systems for colonoscopy in colorectal cancer screening in the Asia-Pacific region (project CAD/NCCH2217). Jpn J Clin Oncol. 2025; 55: 837-40.

Disclosure

The authors have no conflict of interest related with this study.

Introduction

Long-term colorectal cancer (CRC) incidence and mortality after a negative colonoscopy screening remains unclear.

Aims & Methods

We aimed to assess CRC incidence and mortality in individuals with a negative colonoscopy screening according to CRC risk profiles.
We prospectively assessed colonoscopy screening, risk factors, and CRC diagnosis and death among 146,153 women from the Nurses’ Health study I/II and 33,538 men from the Health Professionals Follow-up Study between 1986 and 2017. We compared the CRC incidence and mortality for up to 20 years using Cox regression between individuals with the first reported negative colonoscopy screening and those without colonoscopy screening. We then assessed CRC risk in the negative screening group according to a CRC risk score (range, 0-8) defined by family history, smoking status, body mass index, height, physical activity, alcohol consumption, aspirin use, and diet, including the factors: red meat, processed meat, dietary fiber, dairy products and whole grain.

Results

During a median follow-up of 14 years (interquartile range, 8-20), we documented 1,766 and 436 CRC cases, and 586 and 126 CRC deaths, among participants with no screening and negative screening, respectively. Compared to individuals with no screening, those with a negative screening finding had a stable lower risk, with the multivariable hazard ratio (HR) (95%CI) at 20 years of 0.53 (0.46-0.58) for CRC incidence and 0.42 (0.34-0.51) for CRC mortality. The risk reduction was more substantial for rectal cancer (HR=0.32) and distal colon cancer (HR=0.42) than proximal colon cancer (HR=0.70) (P_{heterogeneity} <0.001). Among individuals with negative screening, we observed a nearly twofold elevation of CRC risk comparing the high-risk (score=5-8) with low-risk (score=0-2) groups (HR=1.99, 95%CI, 1.50-2.63, P_trend <0.001); and using the CRC incidence in the high-risk group at 10 years as the benchmark for surveillance, the low-risk group did not attain the benchmark until ~20 years after screening.

Conclusion

Individuals with a negative colonoscopy screening had a persistent lower risk of CRC incidence and mortality for at least 20 years and may extend their surveillance interval beyond the currently recommended 10 years, depending on their CRC risk factor profile.

Disclosure

Andrew T. Chan has served as a consultant for Bayer Healthcare and Pfizer for work unrelated to the topic of this manuscript. The remaining authors disclose no conflicts.