Original article
Alimentary tract
Consequences of Increasing Time to Colonoscopy Examination After Positive Result From Fecal Colorectal Cancer Screening Test

https://doi.org/10.1016/j.cgh.2016.05.017Get rights and content

Background & Aims

Delays in diagnostic testing after a positive result from a screening test can undermine the benefits of colorectal cancer (CRC) screening, but there are few empirical data on the effects of such delays. We used microsimulation modeling to estimate the consequences of time to colonoscopy after a positive result from a fecal immunochemical test (FIT).

Methods

We used an established microsimulation model to simulate an average-risk United States population cohort that underwent annual FIT screening (from ages 50 to 75 years), with follow-up colonoscopy examinations for individuals with positive results (cutoff, 20 μg/g) at different time points in the following 12 months. Main evaluated outcomes were CRC incidence and mortality; additional outcomes were total life-years lost and net costs of screening.

Results

For individuals who underwent diagnostic colonoscopy within 2 weeks of a positive result from an FIT, the estimated lifetime risk of CRC incidence was 35.5/1000 persons, and mortality was 7.8/1000 persons. Every month added until colonoscopy was associated with a 0.1/1000 person increase in cancer incidence risk (an increase of 0.3%/month, compared with individuals who received colonoscopies within 2 weeks) and mortality risk (increase of 1.4%/month). Among individuals who received colonoscopy examinations 12 months after a positive result from an FIT, the incidence of CRC was 27.0/1000 persons (increase of 4%, compared with 2 weeks), and mortality was 9.1/1000 persons (increase of 16%). Total years of life gained for the entire screening cohort decreased from an estimated 93.7/1000 persons with an almost immediate follow-up colonoscopy (cost savings of $208 per patient, compared with no colonoscopy) to 84.8/1000 persons with follow-up colonoscopies at 12 months (decrease of 9%; cost savings of $100/patient, compared with no colonoscopy).

Conclusions

By using a microsimulation model of an average-risk United States screening cohort, we estimated that delays of up to 12 months after a positive result from an FIT can produce proportional losses of up to nearly 10% in overall screening benefits. These findings indicate the importance of timely follow-up colonoscopy examinations of patients with positive results from FITs.

Section snippets

Methods

For this study, we simulated an average-risk United States population cohort who received annual FIT screening between ages 50 and 75 years. The analyses used the Microsimulation Screening Analysis-Colon (MISCAN-Colon) model developed by the Department of Public Health within Erasmus MC University Medical Center, Rotterdam, the Netherlands. MISCAN-Colon is part of the United States National Cancer Institute’s (NCI’s) Cancer Intervention and Surveillance Modeling Network.9 It has been used to

Colorectal Cancer Outcomes in Fecal Immunochemical Test Positive Patients

Among FIT screening participants with a positive test result, the lifetime risks of CRC incidence and mortality without any diagnostic follow-up were estimated as 82.8 and 34.4 per 1000 patients, respectively. Among patients who had diagnostic colonoscopy within 2 weeks, the risk of CRC was reduced to 35.5 per 1000 (Figure 1A), and the risk of death from CRC was reduced to 7.8 per 1000 (Figure 1B). Of the diagnosed cancers, 57% were stage I, 24% were stage II, 12% were stage III, and 7% were

Discussion

In the absence of high-quality observational data, we used an established microsimulation model to estimate the consequences of different times to colonoscopy after a positive FIT for the benefit and cost of CRC screening. Our results suggest that longer time to follow-up might lead to clinically relevant increases in the risks of CRC, advanced-stage CRC, and CRC mortality. Although FIT screening remained cost saving even with 12 months to follow-up, cancer-related mortality in patients with a

References (33)

  • Peterson K, Carson S, Humphrey L, et al. Patients with positive screening fecal occult blood tests: evidence brief on...
  • Z.F. Gellad et al.

    Time from positive screening fecal occult blood test to colonoscopy and risk of neoplasia

    Dig Dis Sci

    (2009)
  • Cancer Intervention and Surveillance Modeling Network (CISNET). Colorectal cancer model profiles. National Cancer...
  • A.G. Zauber et al.

    Evaluating test strategies for colorectal cancer screening: a decision analysis for the U.S. Preventive Services Task Force

    Ann Intern Med

    (2008)
  • O.D. Jorgensen et al.

    A randomised study of screening for colorectal cancer using faecal occult blood testing: results after 13 years and seven biennial screening rounds

    Gut

    (2002)
  • S.J. Winawer et al.

    Randomized comparison of surveillance intervals after colonoscopic removal of newly diagnosed adenomatous polyps: the National Polyp Study Workgroup

    N Engl J Med

    (1993)
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    Conflicts of interest The authors disclose no conflicts.

    Funding Supported by grants from the National Cancer Institute at the United States National Institutes of Health (#U54 CA163262 and also U01 CA152959, U01 CA151736, U24 CA171524, and P30 CA008748). This material is the result of work supported in part by resources from the VA Puget Sound Health Care System. The views expressed in this article are those of the authors and do not necessarily represent the views of the National Cancer Institute or of the Department of Veterans Affairs.

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