Hollings Horizons Winter/Spring 2026 - Magazine - Page 20
COLON
CANCER
QA
&
Colon cancer is the third most common cause of cancer death for men and the
fourth most common cause of cancer death for women. What do you need to
know about colon cancer screening? Thomas Curran, M.D., explains.
Why is it important to get
screened for colorectal
cancer?
Really, there are two pieces of information.
One is that colorectal cancer is quite
common.
The next thing is that it is a disease that,
unfortunately, may not cause symptoms
until it is quite advanced. That’s where
screening comes into play.
So what are the screening
options?
The United States Preventive Services
Task Force embraces what they refer to
as a “menu of options,” and that, broadly
speaking, has three categories of tests.
One: endoscopic tests like colonoscopy.
Two: stool-based tests like Cologuard or
something called FIT testing, which is
fecal immunohistochemical testing. Three:
imaging-based tests.
Colonoscopy has the highest sensitivity
and specificity, meaning it’s the most
accurate for detecting colorectal cancer.
It also is by far the best test to identify
precancerous lesions – to find polyps
before they can become a cancer and
remove them.
Stool-based tests are also quite accurate
for detecting cancer. They also make
colorectal cancer screening more
accessible.
For average-risk patients, stool-based
tests should be done every one to three
years, depending on the particular test,
and colonoscopies every 10 years.
CT colonography is a noninvasive
imaging approach that uses a CT scanner
to get images of the large intestine. We
usually recommend this method only for
people who aren’t a good fit for either
colonoscopy or stool-based tests.
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What about other screening
methods? Is there anything
new?
The use of blood tests as screening for
colorectal cancer has been looked at as a
kind of Holy Grail for years.
In summer of 2024, there was a
publication of a very large clinical trial in
the New England Journal of Medicine
on a blood test to detect the presence
of colorectal cancer. They looked at
almost 8,000 people who gave a blood
specimen and then had a colonoscopy,
and they found that the sensitivity (how
effective the blood test was in identifying
colon cancer) was high, 83%, and false
positives were pretty low.
That test, called Shield, was FDAapproved in 2024. I think it is something
that is on the horizon as an exciting
technology that perhaps could play a big
role in reaching more people for colorectal
cancer screening.
A current drawback is that it is not so
effective at finding precancerous lesions,
or polyps. It had only 13% sensitivity for
detecting advanced precancerous lesions.
So it is very good at finding cancer, but it
is a less useful tool for finding precancer
and preventing cancer.
Hollings Horizons Winter/Spring 2026
