“Making A Breakthrough Better: Improving Low
Dose CT Scans”
Edward Patz, MD
Edward Patz, MD, James and Alice Chen Professor of Radiology, Professor in Pharmacology
and Cancer Biology at Duke University School of Medicine, talks about how blood biomarkers
and imaging technology can be used together to diagnose lung cancer.
How important have low dose CT scans become in helping diagnose lung cancer?
Dr. Patz: CT scans are used on an everyday basis and they are among the tools that we use to
try to detect lung cancers early. There is the recent National and Cancer Screening Trial, which
did show a reduction in lung cancer mortality, but now we are trying to figure out how to
efficiently put that into large public health screening programs.
What have you discovered that has made CT scans even more effective?
Dr. Patz: One of the biggest problems with the low dose CT screening trials was that a large
percentage of individuals enrolled in those trials had indeterminate pulmonary abnormalities,
meaning they had an abnormality but we were not sure if it was cancer or not cancer. That
occurred in almost 25% of participants. So, we see a large number of individuals who have
these abnormalities, but only a small percent will actually have lung cancer.
What happens when you do see something that is abnormal, but you cannot determine at
that point if it is cancer or not? Does that person have to go for more testing and maybe
invasive surgery?
Dr. Patz: Almost all of those patients will have further evaluation. They could have sequential
studies or multiple sequential studies at 3- to 6-month intervals. They may go for an additional
test, such as a PET scan, which helps us differentiate a benign tumor from a malignant
abnormality. Some of them may go for an invasive procedure, such as a biopsy, or may even go
directly to surgery.
How does your blood biomarker work? What does it do? How does it supplement the CT
scan so people can maybe avoid those procedures?
Dr. Patz: This test draws the patient’s blood. We look at the radiograph, either a CT or a chest
film, because we need to know the size of the nodule, which tells us something about the
likelihood or the risk for lung cancer. We use both to come up with the patient’s risk of lung
cancer, whether it’s high, moderate, or at low risk for lung cancer. At this point we have the
abnormality, we draw the blood test. Then we can develop risk stratification so we can more
efficiently guide patient management.
What is in the blood that you look for?
Dr. Patz: We are looking for three separate proteins and these are proteins we discovered in
the lab, which we found to be higher in patients with cancer rather than those patients without
cancer.
Was that something you guys discovered here?
Dr. Patz: Right, we discovered it right here in the lab.
Would you take the CT image or a chest x-ray?
Dr. Patz: It could be a chest x-ray or a CT image. We combine the two with the blood
biomarkers and we come up with a risk stratification.
How does the procedure work once you have all the information? You have the CT scan
and the blood work, what happens next? How long will it take to get the information back
whether it is high or low risk?
Dr. Patz: Oh, that is very fast. I mean it is back within a day or so. It is simple. We already have
the assay worked out and then we provide the clinician, whoever ordered the test and is taking
care of the patient, with that information. They can then decide on the best way to manage the
patient from there.
Is this widespread at this point? Are you hoping to be widespread?
Dr. Patz: No, we have not really introduced it. The Phase 3 biomarker studies have been
completed and published. So, now we are just trying to introduce this into clinical practice. We
will see what the adoption rate becomes.
So you just kind of got this new toy and you just hope more people will use it?
Dr. Patz: Correct. We think it will be quite useful to manage these patients, which right now
everybody’s fundamentally managed the same. There really is not a good way to separate them
out and then some patients may avoid the risk of biopsy. Instead of 3 months, they may delay a
CT scan to a year and we can then reassure them that the risk is fairly low. The test is not
perfect. We have to tell patients that it is not absolute, but at least it gives us better guidelines
than we had before.
How accurate did it turn out to be in determining the low- and high-risk patients?
Dr. Patz: The overall accuracy of the test is around 80% to 85% accurate. So for the vast
majority of patients we are correct, but that still means approximately 15% to 20% of the
patients will not be accurately determined. We believe that if they have cancer, the risk is still
very low that they will progress in the interim because we are very conservative about the
recommendations. So that they will not progress and it really should not have any detrimental
effect to their long-term outcome.
In that 20% to 15%, did it skew toward diagnosing cancer or did it skew toward not
catching the cancer?
Dr. Patz: We tried to catch as many lung cancer patients as we could with the understanding
that we have more so-called false positive tests. The vast majority of cancers that we did not
pick up were very small nodules, but they were all in the early stage disease and all treated
exactly the same.
If this is adopted, what is the procedure? Do they have to send it to Duke specifically or
do can they do it from their own office?
Dr. Patz: No, this will be a laboratory-based test where they will be able to send it into a central
laboratory and they will perform the test.
So any laboratory they use for other blood work, they can use for this?
Dr. Patz: There probably will be specific laboratories. At this time, the study was performed with
one of the central labs, which was LabCorp. They are the ones who are developing the test, but
they have offices all over the country and they can perform the test anyplace.
Without this, if you saw an abnormality, would it take a lot longer than a day to help a
patient figure out if they had a high or low risk?
Dr. Patz: There is no other way that we know of to determine whether they have a high or low
risk. Right now, we use an algorithm based on size as to how we should manage them.
However, this actually gives us additional confidence to see if what we are doing is correct and
it could actually reduce the risk of scans. It may give the patients more confidence that they do
not have lung cancer or it may tell us that we need to act sooner rather than 3 months and we
may need to be more aggressive about an abnormality.
So it could help speed up treatment if need it or help people avoid it if they do not need
it?
Dr. Patz: That is right.
How long did it take to develop this?
Dr. Patz: It has taken us several years to do the discovery and the initial validation. Then we
just completed the Phase 3, randomized biomarker trial, or the blinded independent study on a
prospective group of patients, and that took several years. So, overall, it has probably been
about 8 years for us to develop the test.
Did the biomarker help Lawrence get treatment faster?
Dr. Patz: I do not know. I cannot tell you if he was. I know he was one of our patients who
consented and we have his blood, whether he was in that prospective trial, I do not know right
now. No he was not. I can tell you, that he did not help him because at the time of the trial you
really cannot use the biomarker to change management until you know that it is really effective.
He is going to be an example of what it is like before this?
Dr. Patz: Yes. He is a patient who would have benefitted from this type of marker.
So, is it being used anywhere at this point?
Dr. Patz: No, it is not. We have not rolled it out yet, but we are in the process of doing that,
trying to make sure that the infrastructure is there.
Do you have any idea when it might be rolled out?
Dr. Patz: That is more of LabCorp’s decision rather than my decision at this point. We
performed the trial. We developed the markers and performed the trials. Now, it is up to them to
help roll this out and make available for clinics.
What is that infrastructure that needs to be built? Can you kind of describe what needs to
be in place in order for this to be?
Dr. Patz: Well, first of all they need to make sure that all their laboratories can perform the tests.
Several of them can now, but need to make sure when they collect the blood that they know that
it is part of this lung cancer management protocol. Hopefully this will make it to where at the
end they give the results of the specific markers, meaning the blood level, but they can also use
this algorithm that are developed by combining the nodule size with the markers to come out
with a risk stratification. That sort of package has not been fully commercialized at this point.
What are you looking for specifically in the proteins? Is it an elevated level of the
proteins?
Dr. Patz: It is an elevated level of the proteins. We found 3 proteins in particular, which were
elevated in patients with lung cancer as compared to patients who did not have lung cancer.
This information is intended for additional research purposes only. It is not to be used as
a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional
interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or
accuracy of physician statements. Procedures or medicines apply to different people
and medical factors; always consult your physician on medical matters.
If you would like more information, please contact:
Edward Patz, Jr., MD
James and Alice Chen Professor of Radiology
Professor in Pharmacology and Cancer Biology
Duke University School of Medicine
(919) 684-7367
patz0002@mc.duke.edu
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