Society: AGA

Background: The Nordic-European Initiative on Colorectal Cancer (NordICC) Study highlighted the impact of adherence on the effectiveness of colonoscopy at reducing CRC incidence and mortality. Within a large, randomized trial comparing colonoscopy to fecal immunochemical testing (FIT) for average risk screening, we previously reported that adherence with annual FIT was initially high (81.6% in year 1) and falls to 59-68% in subsequent years (Gastroenterology 2022;172.7:S-199).

Aim: To determine screening colonoscopy participation and predictors of adherence.

Methods: Eligible participants were age 50-75 years, due for CRC screening and willing to be randomized to colonoscopy vs. FIT at 46 Veterans Affairs medical centers during 2012-2017. Those with first degree relatives with CRC or signs or symptoms of CRC were excluded. Stepwise logistic regression, stratified by site, with p<0.1 for inclusion and p<0.05 criteria for remaining in the multivariable model was used to identify independent associations with colonoscopy adherence at 6- and 12-months.

Results: Among 25,065 colonoscopy-arm participants (mean age 59.1 years), 93.2% were male, 69.8% were White, 24.0% were African American or Black (AA), 1.6% were Asian, 0.8% were American Indian or Alaska Native (AIAN), and 3.7% other race. Hispanic/Latino ethnicity was reported by 11.3%. Overall, 69.3% and 70.7% completed colonoscopy within 6 and 12 months, respectively. At 6 months, the odds of adherence were 12% lower for women vs. men, 15% lower for AA and 43% lower for AIAN vs. Whites, 2% lower per year of age and 29% lower for current vs. never smokers. (Table). The odds of adherence were most positively associated with having had a prior colonoscopy (45% increase) and with having a second degree relative with CRC (17% increase), college degree (16% increase), prior screening with occult blood testing (14% increase) and former smokers (7% increase). The evaluation of 12-month adherence revealed similar findings.

Conclusions: Though colonoscopy adherence (71% at 1 year) was lower than we previously reported for FIT (82% in the first round), it was substantially higher than the 42% reported in the largest randomized colonoscopy study to date (NordICC). Predictors of adherence were different than those we previously reported for FIT. Most notably, age was inversely associated with colonoscopy adherence but positively associated with FIT adherence. Also, FIT adherence was not associated with sex or having a second degree relative with CRC. Our work extends prior studies demonstrating the importance of individual-level factors in predicting screening adherence, including identification of differences by screening strategy. Interventions, especially for those with independent risk factors for non-adherence, are needed to improve screening participation.

*The first two authors are co-first authors.

Background: Patients undergoing evaluation for heart transplant due for colorectal cancer (CRC) screening often undergo colonoscopy, but these patients are at higher risk for procedural complications. At our institution’s high-volume endoscopy suite, these endoscopies routinely involved multi-day delays to coordinate between Gastroenterology and Cardiac Anesthesiology. A multi-disciplinary program was initiated in 2016 wherein appropriate-risk patients in need of CRC screening had CT colonography as the first line screening study and then underwent reflex colonoscopy or sigmoidoscopy if concerning lesions were identified.
Aims: The primary outcome was to determine the number of colonoscopies avoided via CT colonography. A secondary outcome was to compare time-to-completion of CT colonography vs colonoscopy for hospitalized patients.
Methods: This was a retrospective observational chart review of patients who underwent heart transplant evaluation at our tertiary-care, urban hospital pre-intervention (2015) and post-intervention (2016-2022). We reviewed transplant evaluation notes for CRC screening study type. If a patient had colonoscopy or CT colonography, we collected dates and time stamps for study orders, case requests, and Gastroenterology consult orders; inpatient vs outpatient location; CT colonography outcomes; and colonoscopy indications. Time-to-completion for inpatient studies was calculated as the difference between the order or consult date/time and the study date/time. R was used to calculate quartiles and conduct Wilcoxon rank-sum test analysis.
Results: 600 patients were reviewed (56 in 2015 and 544 in 2016-2022). 162 patients had a colonoscopy or CT colonography between 0-180 days after their transplant evaluation start date. In 2015, all 13 screened patients had colonoscopies. Post-intervention, 96 patients (64%) underwent CT colonography, and 53 (36%) had colonoscopies (Fig. 1). All patients who underwent colonoscopy post-intervention were ineligible for CT colonography due to medical history requiring endoscopic evaluation. 13 of 96 (14%) CT colonography studies reflexed to colonoscopy (11 for polyps >5 mm; 2 for wall thickening). During hospitalization, CT colonography was completed in a median of 1.9 days (IQR 1.1-2.8, n=82) from study order, compared to median of 2.6 days (IQR 1.9-5.0, n=20) for colonoscopy (Fig. 2, p=0.014).
Conclusions: This CT colonography program diverted 83 patients from colonoscopy over 7 years, thereby avoiding anesthesia risk, simplifying workflow, and decompressing a high-volume endoscopy suite. CT colonography significantly decreased time-to-completion of a study compared to colonoscopy. Initial screening with CT colonography may be a practical and safe alternative for CRC screening at institutions with similarly high–risk populations. Future exploration will assess cost effectiveness of this approach.

Figure 1: Colorectal Cancer Screening Methods and Sites for Patients Undergoing Heart Transplant Evaluation. Depicts the number of patients who underwent CT colonography (n=82 inpatient at the authors' institution, n=14 outpatient) or colonoscopy (n=31 inpatient at the authors' institution, n=35 outpatient or at another hospital) within 180 days after officially starting their transplant evaluation at the authors' institution.

Figure 1: Colorectal Cancer Screening Methods and Sites for Patients Undergoing Heart Transplant Evaluation. Depicts the number of patients who underwent CT colonography (n=82 inpatient at the authors' institution, n=14 outpatient) or colonoscopy (n=31 inpatient at the authors' institution, n=35 outpatient or at another hospital) within 180 days after officially starting their transplant evaluation at the authors' institution.

Figure 2: Comparison of Time-to-Completion for Inpatient CT Colonography versus Colonoscopy in Patients Undergoing Heart Transplant Evaluation. Plots the time-to-completion (difference between the study order date and time and the study date and time) for patients who underwent CT colonography (n=82) or colonoscopy (n=20) while hospitalized at the authors' institution in 2016-2022. The difference in time-to-completion between the two groups was significant (Wilcoxon rank-sum test, p=0.014).

Figure 2: Comparison of Time-to-Completion for Inpatient CT Colonography versus Colonoscopy in Patients Undergoing Heart Transplant Evaluation. Plots the time-to-completion (difference between the study order date and time and the study date and time) for patients who underwent CT colonography (n=82) or colonoscopy (n=20) while hospitalized at the authors' institution in 2016-2022. The difference in time-to-completion between the two groups was significant (Wilcoxon rank-sum test, p=0.014).

Avinash Kambadakone

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