Comparative Analysis of Fecal Immunochemical Test (FIT) versus Colonoscopy for Colorectal Cancer Screening
Colorectal cancer (CRC) represents a significant health burden globally, being the second leading cause of cancer-related deaths in the United States. Despite the lethal nature of CRC, the implementation of effective screening protocols has significantly reduced its impact. This article reviews the advantages and drawbacks of the two leading CRC screening tests: the fecal immunochemical test (FIT) and colonoscopy, with insights from experts in the field.
The Case for FIT
FIT, a less invasive screening option compared to colonoscopy, has been a subject of considerable debate due to its ease of use and lower risk profile. Dr. Robertson argues for FIT, highlighting its high adherence rates in population-based screenings globally. Studies such as the COLONPREV trial and SCREESCO trial demonstrate higher participation rates and comparable cancer detection rates with FIT over colonoscopy. The simplicity of the FIT test and its application in large-scale mailed screening programs, like those employed by Kaiser Permanente, showcase its practicality and effectiveness in increasing screening adherence.
Challenges with Colonoscopy as a Primary Screening Tool
While colonoscopy is widely regarded as the gold standard for detecting and removing polyps, Dr. Rex and other experts acknowledge its limitations. The test’s invasive nature, potential for complications, and lower participation rates highlight some of the challenges. Furthermore, findings from the NordICC trial suggest that the absolute reduction in CRC mortality with colonoscopy may be less significant than previously believed, raising questions about its efficacy as the most viable primary screening tool.
Effectiveness in CRC Detection and Prevention
Colonoscopy:
- Provides a direct visual examination of the colon, allowing for the detection and removal of polyps.
- Is highly effective in identifying advanced adenomas and sessile serrated lesions, which are significant precursors to CRC.
- The absolute reduction in CRC mortality is less significant than expected, with large-scale trials like the NordICC showing a smaller than anticipated decrease in CRC mortality.
FIT:
- Targets hidden blood in the stool, an indicator of potential CRC.
- Shows reasonable sensitivity for detecting advanced neoplasia, with repeated annual or biennial testing increasing detection rates.
- Less effective than colonoscopy in detecting sessile serrated lesions and some advanced adenomas.
Adherence and Patient Participation
Colonoscopy:
- Generally has lower adherence rates due to its invasive nature and the preparation required before the procedure.
- The complexity and discomfort associated with the procedure can deter routine screening adherence.
FIT:
- Demonstrates higher adherence rates globally, especially in large-scale and population-based screenings.
- Non-invasive and simple to administer, which increases its acceptability among the general population.
Economic Considerations
Colonoscopy:
- While offering comprehensive screening, it is more resource-intensive and costly on a per-procedure basis.
- Longer intervals between screenings might reduce overall costs but require a higher initial resource allocation.
FIT:
- More cost-effective on an annual or biennial basis due to lower per-test costs.
- The economic advantage is particularly notable in settings with limited resources and where high adherence can be maintained.
Healthcare System Integration and Practicality
Colonoscopy:
- Requires significant healthcare infrastructure, including trained specialists and proper facilities.
- Better suited for healthcare systems with ample resources and access to specialized care.
FIT:
- Easier to integrate into various healthcare settings due to its simplicity and non-invasiveness.
- Particularly effective in large-scale screening programs that can be administered through minimal healthcare interactions.
Impact on Health Disparities
Colonoscopy:
- May not be as accessible to underserved populations, contributing to disparities in CRC screening and outcomes.
FIT:
- Has been shown to reduce disparities in screening rates, particularly effective in community-based and mailed screening programs.
- Can be more easily deployed across diverse populations, potentially leveling the playing field in CRC prevention.
Environmental Impact
Colonoscopy:
- Associated with significant environmental impacts due to the consumables used and the need for patient travel to facilities.
FIT:
- Offers a lower environmental footprint, aligning with sustainable health-care practices by minimizing consumable use and patient travel.
Conclusion
Both FIT and Colonoscopy have their unique roles in CRC screening, with each method presenting distinct benefits and limitations. FIT’s higher adherence rates, cost-effectiveness, and lower environmental impact make it an attractive option for large-scale, population-based screenings. On the other hand, colonoscopy’s superior diagnostic accuracy makes it indispensable, especially in high-risk individuals or those with positive FIT results. Ultimately, a balanced approach that utilizes both methods, tailored to patient needs and healthcare capabilities, may offer the most effective strategy for reducing CRC incidence and mortality globally.
Reference
- Robertson DJ, Rex DK, Ciani O, Drummond MF. Colonoscopy vs the Fecal Immunochemical Test: Which is Best? Gastroenterology 2024 May;166:758-771.
