Triage in screening for colorectal cancer
The current general screening for colorectal cancer using an immunochemical test
for occult blood in feces (FIT) has led to identification of many subjects with CRC
and extremely many with high-risk or medium-risk adenomas—a success
generated by the number of subjects with positive FIT-results.
In Denmark all subjects with a positive FIT result are offered subsequent colonoscopy.
Moreover, all subjects with a high-risk or medium-risk adenoma
are offered control colonoscopy after 1 and 3 years, respectively.
In addition, an increasing number of subjects are referred to diagnostic colonoscopy
due to symptoms that may be attributable to bowel cancer.
Hence, in our treatment plans we now experience waiting times for colonoscopy
exceeding the statutory 14 days, by far.
Countrywide, the total need for colonoscopies, currently, exceeds the total investigation capacity.
A need that increases further the screening interval, from 2018,
was reduced from the initially 4 years to 2 years.
Threshold limit value (cut-off)
In Denmark, the threshold value (cut-off) for the amount of occult blood in the feces,
which determines, whether a screened person is offered a subsequent colonoscopy,
is at 100 ng blood per ml stool.
Many European countries with CRC-screening have already been forced
to raise their cut-off value in order to adapt the demand for colonoscopy to the capacity.
Consequently, many subjects with adenoma lesions or CRC
are not identified by the general screening.
Among all colonoscopies, including: screening-derived colonoscopies;
diagnostic colonoscopies (due to symptoms of CRC); and control colonoscopies (due to adenoma control)
─ approx 55-80% are without any findings of adenomas or actual disease.
Methods for a more accurate selection for colonoscopy of only those
who are in real need of further examination
would help balancing needs with capacity─in favor of the health economics;
and also the individual, who avoids an unpleasant (non-risk-free) examination.
Our research results
Our research in blood-based cancer-associated biomarkers shows:
- That a blood-test can be crucial in identification of subjects
with adenomas or the disease colorectal cancer.
- That Triage used in CRC-screening─ie a combination of
(1) age + (2) a stool-test (FIT) result + (3) a blood test—
leads to a more precise selection to colonoscopy of those
for whom a colonoscopy is required.
Accordingly, the number of screening-derived colonoscopies
will be reduced approximately 25%.
International research results
have recently shown that the FIT-test is suitable in selection
for diagnostic colonoscopy due to CRC-symptoms, as well.
Presumably, use of the TRAIGE-concept in selection for diagnostic colonoscopy at CRC-symptoms
could (as well as in screening derived colonoscopies) reduce the total amount of needed colonoscopies.
Triage in selection to diagnostic colonoscopy:
For the purpose of validating the options in using the TRIAGE concept for a more accurate selection
also for diagnostic colonoscopy among subjects with symptoms of CRC:
we have designed a 2-3 year validation study—which was initiated as a pilot late
2018— and fully implementetd during the early springtime 2019:
The Endoscopy IV-project
By reducing the number of diagnostic colonoscopies as well as the screening-derived colonoscopies—(cf. preliminary results)—
the countrywide overall need for colonoscopies could be adapted to the available capacity—and waiting time for a colonoscopy could be eliminated—promoting an earliest possible diagnoses.
Application of research results
The publication on the basic research results:
“Serological biomarkers in triage of FIT-positive subjects?”
See also: Media-coverage
Videnskab.dk (30.11.16) — Jyllands-Posten (01.12.16) — BT (01.12.16