Impact of colorectal cancer screening participation in remote northern Canada: A retrospective cohort study

The impact on clinical outcomes and healthcare resources from discontinuing colonoscopy surveillance subsequent to low-risk adenoma removal: A simulation study using the OncoSim-Colorectal model

OBJECTIVE

To estimate the impact on clinical outcomes and healthcare resource use from recommending that patients with 1-2 low-risk adenomas (LRAs) return to routine fecal immunochemical test (FIT) screening instead of surveillance colonoscopy, from a Canadian provincial healthcare system perspective.

METHODS

The OncoSim-Colorectal microsimulation model simulated average-risk individuals eligible for FIT-based colorectal cancer (CRC) screening in Alberta, Canada. We simulated two surveillance strategies that applied to individuals with 1-2 LRAs (<10 mm) removed as part of the average risk CRC screening program: (a) Surveillance colonoscopy (status quo) and (b) return to FIT screening (new strategy); both at 5 years after polypectomy. A 75 ng/mL FIT positivity threshold was used in the base case. The simulations projected average annual CRC outcomes and healthcare resource use from 2023 to 2042. We conducted alternative scenarios and sensitivity analyses on key variables.

RESULTS

Returning to FIT screening (versus surveillance colonoscopy) after polypectomy was projected to have minimal impact on long-term CRC incidence and deaths (not statistically significant). There was a projected decrease of one (4%) major bleeding event and seven (5%) perforation events per year. There was a projected increase of 4800 (1.5%) FIT screens, decrease of 3900 (5.1%) colonoscopies, and a decrease of $3.4 million (1.2%) in total healthcare costs per year, on average. The annual colonoscopies averted and healthcare cost savings increased over time. Results were similar in the alternative scenarios and sensitivity analyses.

CONCLUSIONS

Returning to FIT screening would have similar clinical outcomes as surveillance colonoscopy but could reduce colonoscopy demand and healthcare costs.

A 5-year evaluation of early-and late-onset sporadic colorectal cancer screening in central Saudi Arabia

BACKGROUND

The Al-Kharj colorectal cancer (CRC) screening program was implemented for five years (2017-2022) in a central urban area of Riyadh Province, Saudi Arabia, to assess the participation and impact of the program in average-risk individuals.

METHODS

The high sensitivity-guaiac based-fecal occult blood test (HSgFOBT) was used as a first-line investigation to identify asymptomatic patients, aged 45-75 years, requiring CRC screening using colonoscopy. The program was run in three tertiary hospitals in the area.

RESULTS

The five-year participation rate was 73% (35,640/48,897). The average age was 53 years (range 45-75), 49% were female (17,464/35,640), all were asymptomatic, and 77% had adequate bowel preparation. The HSgFOBT (+) rate was 6.3% (n = 2245), and 76% (n = 1701) of these underwent colonoscopy. The prevalence of findings were as follows: CRC, 4.8% (81/1701); advanced adenoma, 9.5% (162/1701); adenoma, 15.9% (270/1701); non-adenomatous polyps, 7.9% (135/1701); and no polyps or tumors, 25.4% (432/1701). Among participants aged 45-50 years, early onset-CRC had female predominance, while those ≥50 years with late onset-CRC were predominantly male. CRC was more prevalent in the left colon (P < 0.005).

CONCLUSIONS

Approximately one-third of the participants diagnosed with CRC had early-onset CRC. Screening participation was desirable for the defined target population. Public education is necessary along with expanded colonoscopy resources to continue further citizen participation.

Pandemic-resilient target setting in colorectal cancer screening for vulnerable older population

BACKGROUND

Colorectal cancer screening (CRCS) needs to be pandemic-resilient to avoid long-lasting shutdowns; however, realistic participation target remains unelucidated. This study aimed to identify the lowest acceptable participation rate in CRCS during a pandemic, focusing on vulnerable older populations who require urgent intervention.

METHODS

This nationwide cross-sectional study included 80,946 inpatients aged 70-85 years who were first diagnosed with colorectal cancer (CRC) after 70 years of age, between April 1, 2014 and March 31, 2019, in Japan. To evaluate the association between area-level CRCS participation rate and individual early CRC detection, a multilevel logistic regression model was constructed. The mandatorily implemented screening rates were converted to the total screening rate equivalents (TSREs), which reflect the remaining contributions of voluntarily provided screenings.

RESULTS

Early detections during stages 0-I were significantly observed when primary screening rate was ≥38% (TSRE) and combined follow-up rate was ≥85%. For early detection during Tis-T1, primary screening rate ≥ 38% (TSRE) and combined follow-up rate ≥ 90% were necessary. For follow-up rates ≥70% or ≥75%, there were cases where missed detection of Tis-T1 were observed.

CONCLUSION

The results indicate that, even during pandemic, CRCS should achieve a primary screening rate of 38% and follow-up rate of 85% for vulnerable older populations. These values, lower than the current desirable rates, suggest the maximum possible compromise in balancing the resources between cancer screening and pandemic measures. Moreover, they also indicate the minimum target for shifting to fecal immunochemical test-focused program. Further explorations with varied CRCS settings are necessary for verification.

Participatory simulation modeling to inform colorectal cancer screening in a complex remote northern health system: Canada's Northwest Territories

BACKGROUND & AIMS

Colorectal cancer (CRC) mortality in the Northwest Territories (NWT), a northern region of Canada, could be reduced by implementing a CRC screening program. However, this may require additional colonoscopy resources. We used participatory simulation modeling to predict colonoscopy demand and to develop strategies for implementing a feasible and effective CRC screening program in this complex remote northern health system.

METHODS

Using a participatory simulation modeling approach, we first developed a conceptual model of CRC screening with local collaborators. This approach informed our parameter adjustments of an existing microsimulation model, OncoSim-CRC, using data from a retrospective cohort review of CRC screening between 2014-2019 and secondary data. Model scenarios reflecting program implementation were run for 500 million cases. Validity was assessed, and outputs analyzed with collaborators. Alternative scenarios were developed to reduce colonoscopy demand and results were presented to end-users.

RESULTS

We estimated that colonoscopy demand with a CRC screening program phased-in over 5 years would surpass capacity within 2 years. If demand is met, screen-detected cancers would increase by 110 %, and clinically-detected cases would reduce by 26 % over the next 30 years. We also found that prolonging the phase-in period, or revising adenoma follow-up guidelines would reduce colonoscopy demand while still improving cancer detection. Both strategies were considered feasible by collaborators. The adjusted model was valid, and the projections informed local end-users plans for CRC screening delivery.

CONCLUSIONS

Using participatory simulation modeling, we projected that a screening program would improve CRC detection but surpass current colonoscopy capacity. Phasing-in the screening program and reducing endoscopic adenoma follow-up would enhance feasibility of a CRC screening program in the NWT and help maintain its effectiveness.