Background

Performance characteristics of fecal immunochemical tests (FITs) to screen for colorectal cancer (CRC) have been inconsistent.

Purpose

To synthesize data about the diagnostic accuracy of FITs for CRC and identify factors affecting its performance characteristics.

Data sources

Online databases, including MEDLINE and EMBASE, and bibliographies of included studies from 1996 to 2013.

Study selection

All studies evaluating the diagnostic accuracy of FITs for CRC in asymptomatic, average-risk adults.

Data extraction

Two reviewers independently extracted data and critiqued study quality.

Data synthesis

Nineteen eligible studies were included and meta-analyzed. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of FITs for CRC were 0.79 (95% CI, 0.69 to 0.86), 0.94 (CI, 0.92 to 0.95), 13.10 (CI, 10.49 to 16.35), 0.23 (CI, 0.15 to 0.33), respectively, with an overall diagnostic accuracy of 95% (CI, 93% to 97%). There was substantial heterogeneity between studies in both the pooled sensitivity and specificity estimates. Stratifying by cutoff value for a positive test result or removal of discontinued FIT brands resulted in homogeneous sensitivity estimates. Sensitivity for CRC improved with lower assay cutoff values for a positive test result (for example, 0.89 [CI, 0.80 to 0.95] at a cutoff value less than 20 µg/g vs. 0.70 [CI, 0.55 to 0.81] at cutoff values of 20 to 50 µg/g) but with a corresponding decrease in specificity. A single-sample FIT had similar sensitivity and specificity as several samples, independent of FIT brand.

Limitations

Only English-language articles were included. Lack of data prevented complete subgroup analyses by FIT brand.

Conclusion

Fecal immunochemical tests are moderately sensitive, are highly specific, and have high overall diagnostic accuracy for detecting CRC. Diagnostic performance of FITs depends on the cutoff value for a positive test result.

Primary funding source

National Institute of Diabetes and Digestive and Kidney Diseases and National Cancer Institute.

Objectives

We tested the effectiveness of offering home fecal immunochemical tests (FITs) during influenza vaccination clinics to increase colorectal cancer screening (CRCS).

Methods

In a clinical trial at Kaiser Permanente Northern California influenza clinics in Redwood City, Richmond, South San Francisco, Union City, and Fresno, we randomly assigned influenza clinic dates to intervention (FIT offered) or control (FIT not offered) and compared subsequent CRCS activity.

Results

Clinic staff provided FITs to 53.9% (1805/3351) of intervention patients aged 50 to 75 years. In the intent-to-treat analysis, 26.9% (900/3351) and 11.7% (336/2884) of intervention and control patients completed an FIT, respectively, within 90 days of vaccination (P ≤ .001). The adjusted odds ratio for completing FIT in the intervention versus the control arm was 2.75 (95% confidence interval = 2.40, 3.16). In the per protocol analysis, 35.4% (648/1830) of patients given FIT and 13.3% (588/4405) of patients not given FIT completed FIT within 90 days of vaccination (P ≤ .001).

Conclusions

This intervention may increase CRCS among those not reached by other forms of CRCS outreach. Future research should include the extent to which these programs can be disseminated and implemented nationally.

OBJECTIVES:The effectiveness of fecal immunochemical test (FIT) screening for colorectal cancer depends on timely colonoscopy follow-up of positive tests, although limited data exist regarding effective system-level strategies for improving follow-up rates. METHODS:Using a mixed-methods design (qualitative and quantitative), we first identified system-level strategies that were implemented for improving timely follow-up after a positive FIT test in a large community-based setting between 2006 and 2016. We then evaluated changes in time to colonoscopy among FIT-positive patients across 3 periods during the study interval, controlling for screening participant age, sex, race/ethnicity, comorbidity, FIT date, and previous screening history. RESULTS:Implemented strategies over the study period included setting a goal of colonoscopy follow-up within 30 days of a positive FIT, tracking FIT-positive patients, early telephone contact to directly schedule follow-up colonoscopies, assigning the responsibility for follow-up tracking and scheduling to gastroenterology departments (vs primary care), and increasing colonoscopy capacity. Among 160,051 patients who had a positive FIT between 2006 and 2016, 126,420 (79%) had a follow-up colonoscopy within 180 days, including 67% in 2006-2008, 79% in 2009-2012, and 83% in 2013-2016 (P < 0.001). Follow-up within 180 days in 2016 varied moderately across service areas, between 72% (95% CI 70-75) and 88% (95% CI 86-91), but there were no obvious differences in the pattern of strategies implemented in higher- vs lower-performing service areas. CONCLUSIONS:The implementation of system-level strategies coincided with substantial improvements in timely colonoscopy follow-up after a positive FIT. Intervention studies are needed to identify the most effective strategies for promoting timely follow-up.

Uptake of colorectal cancer screening remains suboptimal. Mailed fecal immunochemical testing (FIT) offers promise for increasing screening rates, but optimal strategies for implementation have not been well synthesized. In June 2019, the Centers for Disease Control and Prevention convened a meeting of subject matter experts and stakeholders to answer key questions regarding mailed FIT implementation in the United States. Points of agreement included: 1) primers, such as texts, telephone calls, and printed mailings before mailed FIT, appear to contribute to effectiveness; 2) invitation letters should be brief and easy to read, and the signatory should be tailored based on setting; 3) instructions for FIT completion should be simple and address challenges that may lead to failed laboratory processing, such as notation of collection date; 4) reminders delivered to initial noncompleters should be used to increase the FIT return rate; 5) data infrastructure should identify eligible patients and track each step in the outreach process, from primer delivery through abnormal FIT follow-up; 6) protocols and procedures such as navigation should be in place to promote colonoscopy after abnormal FIT; 7) a high-quality, 1-sample FIT should be used; 8) sustainability requires a program champion and organizational support for the work, including sufficient funding and external policies (such as quality reporting requirements) to drive commitment to program investment; and 9) the cost effectiveness of mailed FIT has been established. Participants concluded that mailed FIT is an effective and efficient strategy with great potential for increasing colorectal cancer screening in diverse health care settings if more widely implemented.