13-05-2025
Colorectal Cancer Screening Choices: What's the Best FIT?
Hi, everyone. I'm Dr Kenny Lin. I am a family physician and associate director of the Lancaster General Hospital Family Medicine Residency, and I blog at Common Sense Family Doctor .
Kenneth W. Lin, MD, MPH
Not long after the US Preventive Services Task Force first recommended colonoscopy as a screening method in 2002, I started giving lectures that argued fecal immunochemical testing (FIT) was still a comparable option because patients generally find FIT more convenient than colonoscopy and the mortality benefit of FIT has been proven in several randomized controlled trials.
However, over the past two decades, colonoscopy has become the most commonly used screening test for colorectal cancer in the United States. Newer noninvasive screening options that I discussed in a previous Medscape commentary are also being promoted as superior options to FIT. So, will FIT continue to play a role in colorectal cancer screening?
In a word…absolutely.
Several ongoing randomized trials are evaluating the efficacy of FIT vs screening colonoscopy. In the COLONPREV trial conducted in Spain, 57,000 adults at average risk for colorectal cancer aged 50-69 years of age were randomly assigned to receive an invitation for either a single colonoscopy or FIT every other year. According to results published last month in The Lancet , 55 people in the colonoscopy group and 60 people in the FIT group had died of colorectal cancer at the 10-year endpoint — a difference that was not statistically significant.
There are two main drawbacks to this population-based study: Less than 40% of participants received either screening test, and more than 1 in 3 persons assigned to the colonoscopy group chose to have FIT instead. These issues are understandable, because a minority of eligible adults in Spain have routine colorectal cancer screening and colonoscopy plays a much smaller role as an initial screening test compared to its use in the United States. On the positive side, the study showed that 18% fewer people needed colonoscopy in the FIT group compared with the colonoscopy-first group, and there was no significant difference in cancer deaths.
Although FITs are a widely available and cost-effective option for colorectal cancer screening, FIT efficacy is largely dependent on patient adherence and follow-up compliance; FIT is only effective if patients return stool samples to the lab and get a timely follow-up colonoscopy if they receive an abnormal result. Fortunately, there is a growing body of research focused on exploring strategies to enhance adherence to FIT.
To evaluate patient sentiments regarding FIT screening, investigators in Iowa, North Carolina, and Texas distributed a questionnaire about five different FITs to patients who were scheduled for a screening or surveillance colonoscopy. The investigators found that study participants strongly preferred sample collection in a liquid vial as opposed to a card and made more errors with the latter type. The TEMPO trial also found that the language included in patient instructions can significantly affect follow-up compliance. The addition of one sentence suggesting a 2-week deadline for FIT return (rather than leaving it open-ended) increased overall test return rates and reduced the need to send reminders. Furthermore, results from a cluster randomized trial conducted across 28 clinics in rural Oregon indicate that mailed FIT outreach and telephone-based patient navigation following an abnormal FIT result improved colorectal cancer screening rates at 6 months and diagnostic colonoscopy completion rates at 1 year.
These study findings have important applications for primary care practice. When reviewing colorectal cancer screening test choices with patients, family physicians can continue to recommend annual or biennial FIT as a comparable option to colonoscopy. If FIT is selected, we should provide a kit with liquid vial sample collection, if possible, and include a suggested return date in patient instructions. Finally, clinicians in leadership and population health management roles should advocate for cost-effective investments in patient navigation to enhance colorectal cancer screening and diagnostic colonoscopy completion rates, because these initiatives play a crucial role in preventing colorectal cancer deaths.
