COVID-19 Vaccine and Pet Scans
October 18, 2021Information
October 17, 2021
Yale Cancer Center
visit: http://www.yalecancercenter.org
email: canceranswers@yale.edu
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- 00:00Funding for Yale Cancer Answers
- 00:02is provided by Smilow Cancer
- 00:04Hospital and AstraZeneca.
- 00:08Welcome to Yale Cancer Answers with
- 00:10your host doctor Anees Chagpar.
- 00:12Yale Cancer Answers features the
- 00:14latest information on cancer care by
- 00:17welcoming oncologists and specialists
- 00:18who are on the forefront of the
- 00:21battle to fight cancer. This week,
- 00:22it's a conversation about nuclear
- 00:24medicine and cancer management with
- 00:26Doctor Darko Pucar. Dr. Pucar is
- 00:28an associate professor
- 00:30of radiology and biomedical imaging
- 00:32at the Yale School of Medicine,
- 00:34where Dr. Chagpar is a professor
- 00:37of surgical oncology.
- 00:40Darko, maybe we can start off by you
- 00:41telling us a little bit about
- 00:43yourself and about what you do.
- 00:45I am a nuclear radiologist.
- 00:48That means I have received training in
- 00:51general radiology and nuclear medicine.
- 00:53In my case I did that
- 00:54at Cornell and Sloan
- 00:56Kettering and I'm certified by the
- 00:58American Board of Radiology and
- 01:01the Board of Nuclear Medicine.
- 01:03I also have a science degree from
- 01:06Mayo Clinic and I provide clinical
- 01:08service and I conduct research
- 01:10in general nuclear medicine.
- 01:13and nuclear medicine therapy,
- 01:16and aeronautics,
- 01:16which I will explain in a minute.
- 01:19Let's breakdown
- 01:21some of those things,
- 01:24tell our audience a little bit more about
- 01:27what exactly is nuclear medicine.
- 01:30We do use radioactive
- 01:34tracers to detect cancer,
- 01:37monitor cancer, and treat cancer.
- 01:39So radioactive tracers are a chemical
- 01:42compound in which one or more
- 01:45atoms have been replaced by radioisotope
- 01:48in the process that we call labeling.
- 01:50So these chemical compounds are
- 01:52participants in body functions that
- 01:54are usually altered by cancer,
- 01:57and we have two options.
- 02:01One is to label the
- 02:03radioisotope with the gamma rays,
- 02:05in which case we can
- 02:07produce images or we can
- 02:09use radioisotopes that
- 02:11emit the high energy particles,
- 02:13in which case we can kill the cancer.
- 02:15It sounds like nuclear
- 02:17medicine has a role to play both in
- 02:20diagnostics as well as in therapeutics.
- 02:23So let's look at the diagnostics.
- 02:25To begin with, many of
- 02:27us have heard about PET scans.
- 02:29Is that really the main modality
- 02:31that's used in nuclear medicine
- 02:33for cancer and tell us a little
- 02:35bit more about how that works?
- 02:38Yeah, you are absolutely right.
- 02:40PET scans really are the main modality
- 02:43used for cancer diagnostics,
- 02:45and it's basically a hybrid machine
- 02:48or hybrid scanner that consists of
- 02:51the CT scanner which is X ray
- 02:53machine that produced 3D map of body
- 02:56density and of the PET scanner,
- 02:58which is basically a gamma ray
- 03:01detector machine that again gives
- 03:03us 3D map of tracer distribution
- 03:05in the body and then at the end
- 03:08you fuse CT and PET images to get images
- 03:11that show both anatomy and function in
- 03:15the normal tissue and in the cancer.
- 03:18Do all cancer patients get a pet CT?
- 03:21Or is this only for particular patients?
- 03:25Well, it would depend from cancer to cancer,
- 03:28but usually PET scans in most
- 03:31cancers but not in all I use for
- 03:34more advance patients with cancer.
- 03:36So those are the patients where
- 03:39the cancer is either very large locally,
- 03:42it is spread to the nodes nearby
- 03:44to the cancer site or has
- 03:47metastasized to distant body sites.
- 03:50And so the pet scan really gives
- 03:52us an idea of how far the cancer
- 03:54has spread. Is that right?
- 03:56Absolutely, and the
- 03:57main advantage of the PET scan is that it
- 04:00can detect very small lesions that
- 04:02are not visible on the conventional
- 04:04imaging like a CAT scan or MRI.
- 04:07But then you also mentioned that the
- 04:11same nuclear medicine technologies
- 04:12can be used in the therapeutic arena.
- 04:16So tell us more about that.
- 04:18Yeah, so this is very exciting development.
- 04:21I mean for years we have treated cancers,
- 04:24but it was mostly limited to the
- 04:27iodine treatment for thyroid cancer.
- 04:29But now we are getting many new exciting
- 04:32compounds for prostate cancer for
- 04:34the new rendering tumors and probably
- 04:37would spread to other cancers as well.
- 04:40There are two types of
- 04:43therapies that we conduct.
- 04:45One is if we use chemical
- 04:49compounds that image
- 04:51these high energy particles
- 04:53to kill the cancer,
- 04:55but we do imaging still with a
- 04:58conventional PET scan which
- 05:00usually maps the glucose.
- 05:02It's called fluorodeoxyglucose and
- 05:03then there is a new exciting process
- 05:06which is called theranostics in which
- 05:08we can use the same chemical compound
- 05:10which is important to the function of
- 05:12cancer which are labeled either
- 05:15with the isotopes that can be detected
- 05:18by gamma ray detectors and give us
- 05:22imagine or it can be labeled with a high
- 05:24energy particles and kill the cancer.
- 05:26So probably the most common
- 05:29examples that are probably even
- 05:31known to our audience is dotatate
- 05:36and is the treatment for neuroendocrine cancer.
- 05:38So if we label them with
- 05:41some isotopes like gallium 68
- 05:42we will get images but we can label
- 05:45with other allies like lutetium,
- 05:47in which case we can kill the cancer
- 05:50and what is up and coming and many
- 05:53prostate cancer patients are
- 05:54waiting for that eagerly is to get
- 05:57both imaging and treatment with
- 06:00prostate specific membrane antigen.
- 06:02It sounds like these
- 06:05technologies, if you're able
- 06:07to identify a specific antigen,
- 06:09a specific protein on a particular cancer,
- 06:14and target that with a particle that
- 06:17can kill it, it would seem to me
- 06:19that this would be a very specific
- 06:21way to kill cancer cells.
- 06:24You are correct. So in most cases
- 06:27our therapy has produced results that
- 06:30are comparable to other systemic
- 06:32therapy like chemotherapy but with
- 06:35substantially lower adverse effects.
- 06:37So we kind of achieve similar results
- 06:41but with less morbidity to our patients.
- 06:45Is this widely available or is
- 06:47this still in the research arena
- 06:49and undergoing clinical trials?
- 06:54As I mentioned before,
- 06:56we had iodine for treatment
- 06:59of thyroid cancer for decades,
- 07:02and more recently we have an already
- 07:05clinically approved drug,
- 07:07which is called Xofigo,
- 07:08which is actually labeled
- 07:10radioactive labeled radium,
- 07:11that can kill metastatic disease
- 07:13from prostate cancer in the bone,
- 07:16and most recently
- 07:17and obviously they've got a lot
- 07:19of press attention is lutera,
- 07:22which is again labeled
- 07:23dotatate that can kill
- 07:26advanced neuroendocrine tumors.
- 07:28And for those that are approved
- 07:32are those now taking over instead
- 07:36of being treated with chemotherapy,
- 07:38or are these now being treated
- 07:40with these theranostics?
- 07:45It's more like they're
- 07:48getting incorporated in the treatment
- 07:51algorithms, our patients might have heard
- 07:54there is something called the
- 07:57National Comprehensive Network which
- 07:59is a body that provides all these
- 08:01guidelines how the cancers are treated and
- 08:03slowly the radionuclide therapies are
- 08:06getting incorporated in those guidelines
- 08:09and are used when appropriate
- 08:12to treat advanced or metastatic cancer.
- 08:16Help me to understand
- 08:18that a bit better.
- 08:19I mean because on the one hand it
- 08:21sounds like this is so exciting, right?
- 08:23That these theranostics,
- 08:26if they can truly target
- 08:29these cancers and kill them,
- 08:32and they're specific enough in the
- 08:35sense that you know this is how
- 08:37we look for cancers on imaging,
- 08:40and so we know that
- 08:43they're very specific and don't have all
- 08:45of the side effects of chemotherapy.
- 08:48Why haven't they been widely adopted yet?
- 08:51What's the downside?
- 08:53Well, each cancer and each
- 08:56cancer stage is kind of different, so
- 09:00for example, in thyroid cancer it is
- 09:03generally given after a thyroidectomy,
- 09:08which is removal of the thyroid
- 09:10and after radioactive iodine
- 09:12is given most patients get cured,
- 09:15so thyroid cancer is a relatively
- 09:17well behaving cancer.
- 09:18So in this particular cancer we can actually
- 09:22achieve cure. In some other cancers,
- 09:24for example metastatic prostate cancer,
- 09:26when we are going to use
- 09:30radioactive isotopes we will have actually
- 09:32to prove that they have advantages
- 09:36versus other chemotherapy options,
- 09:39which requires large trials and
- 09:42I don't know if our patients have
- 09:44heard of different lines of chemotherapy,
- 09:46usually there is a first line and
- 09:48then if there is a progression
- 09:50second and third line and so on.
- 09:51So you not only have to prove
- 09:54that they generally work,
- 09:55but you have to find appropriate lines
- 09:57of the therapy for those tracers.
- 09:59So this is now in the
- 10:01process of active research.
- 10:03So basically they have in a way
- 10:06similar limitations as a chemotherapy,
- 10:09despite much lower side effects.
- 10:12If that cancer is very bad,
- 10:15like advanced castrate
- 10:17resistant prostate cancer,
- 10:19they will have less impact because
- 10:21the cancer is already so aggressive.
- 10:23But if thyroid cancer,
- 10:24for example,
- 10:26that cancer is relatively
- 10:27well behaving,
- 10:29then we actually can achieve cure.
- 10:31So basically,
- 10:32in the first situation we will
- 10:34buy time for the patients to
- 10:37give them longer survival.
- 10:38While in this version of thyroid
- 10:40cancer will actually achieve the cure.
- 10:43It sounds like there's
- 10:46still clinical trials ongoing
- 10:48to kind of evaluate the optimal
- 10:50situation in which these theranostics
- 10:52should be used. Is that right?
- 10:55Yeah, that's absolutely correct.
- 10:56So for the neuroendocrine tumors
- 10:59and prostate we'll actually be
- 11:00evaluating what are the optimal
- 11:02situations to be used. In the other cancer there
- 11:06are still not agents that
- 11:09are either approved clinically
- 11:11or approved for trials.
- 11:14There will be a so-called early
- 11:15phase one and phase two studies
- 11:17to see whether they work at all.
- 11:19So at the moment again, thyroid,
- 11:22prostate and NETs are where
- 11:25Radionuclide therapies
- 11:26have advanced the most.
- 11:28Are there other cancers
- 11:30that are on the horizon?
- 11:31Are there other advances that you're
- 11:34particularly excited about?
- 11:36I just laughed a little bit about
- 11:38this because we're getting so many
- 11:40contacts from the pharmaceutical
- 11:42companies there are almost tracers
- 11:44for every cancer that you can imagine,
- 11:47but they will have to pass through
- 11:49phase one and phase two trials to see
- 11:52which of these tracers would make
- 11:54sense to develop as clinical agents.
- 11:58And tell us a little bit more about the
- 12:00side effects of these theranostics because
- 12:03it sounds like with them being so targeted,
- 12:06granted you know it makes a
- 12:08difference how aggressive the cancer
- 12:10is and how far gone it is,
- 12:12but do they have a lot of side effects?
- 12:14Because it seems to me that when
- 12:17we talk on the show about chemotherapy,
- 12:20chemotherapy really targets many cells.
- 12:23Any rapidly dividing cell,
- 12:25which is why they cause
- 12:28things like hair loss and bone
- 12:30marrow suppression and so on,
- 12:32because these are rapidly dividing cells.
- 12:34But in the situation where
- 12:38a protein that is very specific to a
- 12:41cancer can be targeted and almost like
- 12:44a laser killed by these theranostics.
- 12:48One would imagine that the side
- 12:50effects are different,
- 12:52perhaps more local.
- 12:53Tell us about the side effects that
- 12:56patients who are undergoing therapies
- 12:58with these agents might face?
- 13:00That's a little bit surprising,
- 13:03but you have to remember before
- 13:06the tracer gets localized
- 13:08to the tissue of interest,
- 13:10it still stays for awhile in the blood and
- 13:13to some extent goes to the bone marrow.
- 13:16So unfortunately, even through the radio tracers,
- 13:19although we have less
- 13:21toxicity to the bone marrow,
- 13:23patient still can get bone marrow toxicity,
- 13:26which can drop their blood counts,
- 13:28although this is very,
- 13:30very less pronounced with
- 13:32radionuclide tracers than with the
- 13:34conventional chemotherapy and then
- 13:36other side effects are
- 13:38more dependent on how they
- 13:41are eliminated from the body.
- 13:43So for example,
- 13:44for NETs we worry about
- 13:47kidneys because that's where they
- 13:49accumulate a lot when we get they get
- 13:53eliminated or in let's say
- 13:56prostate cancer, we worry about
- 13:59GI tract because patients sometimes
- 14:01get GI side effects.
- 14:03So again, it's a degree of toxicity,
- 14:06but unfortunately pretty much
- 14:09every systemic treatment would,
- 14:11to some extent have a bone
- 14:12marrow side effect.
- 14:13Well we're going to take
- 14:16a short break for medical minute,
- 14:18and when we come back we'll talk a
- 14:20little bit more about some of your work
- 14:22looking at COVID-19 vaccine and its
- 14:25effect on PET scans. Please stay
- 14:27tuned to learn more with my guest
- 14:29Doctor Darko Pucar.
- 14:31Funding for Yale Cancer Answers
- 14:33comes from AstraZeneca, dedicated
- 14:35to advancing options and providing
- 14:37hope for people living with cancer.
- 14:40More information at AstraZeneca Dash us.com.
- 14:46The American Cancer Society estimates that
- 14:48over 200,000 cases of Melanoma will be
- 14:51diagnosed in the United States this year,
- 14:53with over 1000 patients in Connecticut alone.
- 14:56While Melanoma accounts for only
- 14:59about 1% of skin cancer cases,
- 15:01it causes the most skin cancer deaths,
- 15:04but when detected early,
- 15:06it is easily treated and highly curable.
- 15:08Clinical trials are currently underway
- 15:11at federally designated Comprehensive
- 15:13cancer centers such as Yale Cancer
- 15:15Center and at Smilow Cancer Hospital
- 15:17to test innovative new treatments
- 15:19for Melanoma.
- 15:20The goal of the specialized programs
- 15:22of research excellence and Skin
- 15:24Cancer Grant is to better understand
- 15:26the biology of skin cancer
- 15:28with a focus on discovering
- 15:30targets that will lead to improved
- 15:32diagnosis and treatment.
- 15:34More information is available at
- 15:37yalecancercenter.org. You're listening
- 15:39to Connecticut Public Radio.
- 15:42Welcome
- 15:42back to Yale Cancer Answers.
- 15:44This is doctor Anees Chagpar
- 15:45and I'm joined
- 15:47tonight by my guest Doctor
- 15:48Darko Pucar and we're talking
- 15:51about nuclear medicine and before
- 15:53the break we spent some time
- 15:55talking about the role that nuclear
- 15:58medicine plays both in diagnosis
- 16:00as well as potentially in the
- 16:02therapeutic management of cancer.
- 16:04But Doctor Pucar has
- 16:07done some interesting work
- 16:09looking at the impact of COVID-19
- 16:12Vaccine on PET scans.
- 16:14Darko, tell us a little bit
- 16:16more about that.
- 16:18Thank you for this question.
- 16:19This is actually something very
- 16:21exciting to myself and my team members
- 16:24because we kind of anticipated once
- 16:27the vaccine started rolling out that
- 16:29we're going to see some active lymph
- 16:33nodes at the site of vaccine injection.
- 16:36So if, let's say you would get
- 16:39injection in the left deltoid muscle,
- 16:41you are expected to get
- 16:43activity in the left armpit.
- 16:45We kinda knew that was going to
- 16:47happen because that was happening
- 16:49with influenza and since last fall
- 16:53influenza was given relatively rapidly
- 16:55because we are actually seeing
- 16:58for like a week or several weeks
- 17:02actually influenza active lymph nodes.
- 17:05So we were already prepared as soon as
- 17:09COVID vaccine rollout is expected to
- 17:12start collecting the data immediately.
- 17:14So we were collecting actually
- 17:16the data for all the patients that
- 17:19had a pet scan at Yale will first
- 17:21try to determine whether they had
- 17:23COVID vaccine or not,
- 17:25and then we'll assess whether
- 17:27they have active nodes or not.
- 17:29And in the beginning the collection
- 17:31was relatively easy because all
- 17:33the vaccines were administered at
- 17:35Yale so we could get a very precise
- 17:37understanding who had vaccine,
- 17:39who didn't and
- 17:41which type of the vaccine.
- 17:44So we have collected those data as
- 17:47quickly as possible and we published
- 17:50the JAMA article on 68
- 17:53patients that actually had vaccine,
- 17:55listing the frequency of positivity in
- 17:58Pfizer and Moderna vaccines,
- 18:01which is kind of useful to the
- 18:03practitioner as we'll discuss.
- 18:05So tell me more. What did
- 18:07you find and what happened?
- 18:09So basically the reason why we
- 18:12really wanted to know this is because
- 18:15these lymph nodes theoretically
- 18:17can mimic cancer, which would be
- 18:19like a false positive finding.
- 18:21Or they can mask cancer.
- 18:22If we think that these nodes from
- 18:25the vaccine but actually turn out
- 18:27to be nodes from the cancer.
- 18:30So in order to avoid the errors,
- 18:33we kind of need everyone to participate.
- 18:36Both the patients, the providers
- 18:39that are administering the vaccines,
- 18:41the oncologists and us in
- 18:43the nuclear medicine. So it
- 18:45is very important to know the date,
- 18:48the type and the dose and the
- 18:50site of vaccine administration.
- 18:53Also, it is very important to
- 18:56avoid administering the vaccine
- 18:59on the side where cancer might be.
- 19:02So, for example,
- 19:03if you have a right breast cancer,
- 19:05you shouldn't be getting vaccine
- 19:07in the right arm.
- 19:08You should be getting the vaccine
- 19:10in the left arm.
- 19:11Similarly for other cancers that
- 19:13will go to the axilla like Melanoma,
- 19:16for other cancers like lymphoma,
- 19:18it gets more complicated because
- 19:20they can go to different nodes,
- 19:24but it's important to see whether,
- 19:25for example, they had nodes
- 19:28in one versus the other armpit,
- 19:30to determine which arm,
- 19:32which side would be more safe
- 19:35to inject and for patients
- 19:37it is extremely important to tell
- 19:40their oncologist that they will be
- 19:43getting the vaccine if they have some
- 19:45of those cancers that I mentioned
- 19:47to tell the person who is giving
- 19:50the vaccine to avoid the side,
- 19:52which can be confusing.
- 19:54And when they get their PET questionnaire,
- 19:57which is like a survey that we
- 19:59administer prior to PET scan,
- 20:01and that's a good idea
- 20:03even if they didn't get the vaccine,
- 20:08they should ask to see the chart or in epic,
- 20:10but they should actually list if
- 20:12they have any acute symptoms.
- 20:15Especially something that
- 20:17looks like inflammation,
- 20:18and they also should provide information as to
- 20:21when did they get vaccine?
- 20:23What kind of vaccine,
- 20:24and in which side of the arm
- 20:27in left or the right?
- 20:31For example, our data have demonstrated that
- 20:33those reactive nodes that can either
- 20:36mimic or mask cancer and more commonly
- 20:39after second dose of the vaccine,
- 20:42then after the first dose of vaccine
- 20:44which you would kind of expect based
- 20:47on immunologic phenomenons
- 20:49that come with the vaccines.
- 20:50And we also found that they are a
- 20:52little bit more common with
- 20:54Moderna than with Pfizer vaccine.
- 20:56So how long does the
- 21:00effect last on the PET scan?
- 21:02So for example,
- 21:04let's say you got the vaccine today.
- 21:08How long after that would you
- 21:10anticipate that you would still
- 21:12be able to see those enlarged
- 21:15lymph nodes by pet after today?
- 21:18That's a great question. And actually,
- 21:20when we did our original article,
- 21:22we couldn't answer that question
- 21:24because we had relatively few patients.
- 21:27I cannot discuss
- 21:29too much because we have to finish
- 21:30the analysis, so I don't want to be giving
- 21:34statements ahead of the statistician,
- 21:36but based on our preliminary data
- 21:39now of several hundred patients,
- 21:41it seems that probably it would take
- 21:45at least several weeks
- 21:49for the vaccine effect to disappear,
- 21:53and it seems again,
- 21:54this is probably too early,
- 21:57the final word is that it lasts
- 22:00a little bit longer with Moderna than
- 22:01Pfizer.
- 22:04I think that some of the things that
- 22:06you're saying make intuitive sense, right?
- 22:09If you have a known right breast cancer
- 22:13or known right arm Melanoma there,
- 22:17getting an injection on that right
- 22:19side can certainly be confusing
- 22:21to a radiologist who's trying to
- 22:23interpret whether the lymph nodes
- 22:25look ugly because of the cancer
- 22:27or look ugly because of the vaccine.
- 22:30But the
- 22:31other point though,
- 22:33is that you may have gotten the
- 22:36shot without knowing that you also
- 22:38were going to develop a cancer
- 22:40and then find the cancer later,
- 22:43and so that's where things get a
- 22:47little bit tricky when one didn't
- 22:50know about the other diagnosis.
- 22:53That's absolutely right.
- 22:56However, most of the time when
- 22:59we do PET scans prior to actual
- 23:02diagnosis of cancer is for lung
- 23:06nodules and fortunately lung cancer
- 23:09very, very rarely goes to the armpit,
- 23:12so in that situation we'll know based on
- 23:16the expected distribution.
- 23:19It will be obviously more difficult
- 23:21if a patient eventually gets
- 23:24diagnosed with lymphoma.
- 23:26And then it could in some time
- 23:29there are unfortunately few cases
- 23:31that we couldn't really tell,
- 23:33but although it looks really ominous,
- 23:38it is a relatively small number of cases
- 23:41that after careful analysis that we
- 23:43cannot determine what's going on and
- 23:46those we'll have to closely follow up,
- 23:48obviously.
- 23:49So you know getting to the point of
- 23:52the people with lymphoma, for example,
- 23:55where you know it would be expected
- 23:57that you would have many enlarged lymph
- 23:59nodes trying to distinguish that versus
- 24:03response to a COVID
- 24:05vaccine must be pretty difficult.
- 24:07What kind of tools do you
- 24:09use as a nuclear medicine physician
- 24:11who interprets these scans to tell
- 24:13the difference one to the other?
- 24:16Or is this something that relies on a biopsy?
- 24:20I'm hoping that in most cases we
- 24:23really do not need the biopsy and
- 24:25we actually didn't comment on the result to
- 24:27biopsy
- 24:29because, for example,
- 24:31the activity after vaccine
- 24:35is usually not very, very high.
- 24:38So if patients have a disease like
- 24:41a diffuse large B cell lymphoma,
- 24:43those have very higher activity
- 24:45than it would be with the vaccine.
- 24:52The other thing is patients,
- 24:54for example,
- 24:55has disseminated disease.
- 24:58At that point, it may not be necessary
- 25:01to make a distinction for the axilla,
- 25:04because if they are in all
- 25:05other locations on the body,
- 25:07it won't change the management
- 25:09where I kind of see this could be
- 25:12really a problem if a patient has a
- 25:14so-called low grade lymphoma which
- 25:17do not have very high activity and
- 25:19we find isolated nodes in
- 25:24let's say bilateral axilla.
- 25:27So then it would be great,
- 25:30then we'll presume, I guess,
- 25:31in one axilla that is probably
- 25:33due to lymphoma,
- 25:35the one which is not injected.
- 25:36But the injected axilla
- 25:38probably won't know unless we
- 25:40as you said we do the biopsy
- 25:43and presumably you can tell
- 25:46the difference between enlarged
- 25:48lymph nodes that are due to benign
- 25:51conditions like sarcoid or other
- 25:53things versus the COVID vaccine on
- 25:56these PET scans. Is that right?
- 25:59In principle yes,
- 26:01because sarcoid would tend to be in the
- 26:06nodes around the heart industry.
- 26:09In the area that we call media Steinem.
- 26:11While the vaccine nodes
- 26:13would tend to be in armpit,
- 26:15although this differentiation
- 26:16again is not absolute.
- 26:19But since we still rarely image circulated,
- 26:24let's say independently from the cancer,
- 26:28that's way less common situation.
- 26:31That would happen really
- 26:33to be a diagnostic dilemma,
- 26:35and so now that we're kind of in the
- 26:39the scenario where you know people
- 26:41are now thinking about booster shots,
- 26:44do you think that that's going to
- 26:46cause even more of a conundrum?
- 26:48You saw that the lymph
- 26:51nodes were more reactive on pet after
- 26:54the second dose of the COVID vaccine.
- 26:58Do you think that's going to be
- 26:59the case after the third dose?
- 27:02Well, that's a very interesting question
- 27:04so far I have seen only two cases
- 27:07after the booster and one was active.
- 27:10The other was not active,
- 27:11but I didn't have dilemma because based on
- 27:13the other characteristics or cancers
- 27:16and knowing where the vaccine was,
- 27:18I was able to confidently say.
- 27:20But I would also want to bring
- 27:23another interesting point which we
- 27:24are actually going to investigate.
- 27:28We can view those nodes after
- 27:31vaccine as negative because it can
- 27:34create a diagnostic confusion,
- 27:36but we are also hoping to investigate
- 27:39whether activity of these nodes actually
- 27:41can predict the efficacy of the vaccines.
- 27:45And this is for example,
- 27:49there is an Israeli study
- 27:52and they showed that
- 27:54the activity in the nodes
- 27:56correlate with the level of anti
- 27:59spike which is that protein that is
- 28:02very important in COVID antibodies.
- 28:04So basically there was a correlation
- 28:07between activity in these nodes
- 28:10and antibody levels which in a way
- 28:13would reflect the potential level of
- 28:16protection that people would have.
- 28:18So maybe in the future we can not
- 28:21only be threatened by this phenomena,
- 28:24but maybe we can
- 28:25even use iy to predict what level of
- 28:28immunity cancer patients would achieve.
- 28:31Doctor Darko Pucar is an associate
- 28:33professor of radiology and biomedical
- 28:35imaging at the Yale School of Medicine.
- 28:38If you have questions,
- 28:39the addresses cancer answers at
- 28:41yale.edu and past editions of the
- 28:44program are available in audio and
- 28:46written form at Yale Cancer Center Org.
- 28:48We hope you'll join us next week to
- 28:50learn more about the fight against
- 28:52cancer here on Connecticut Public
- 28:54radio funding for Yale Cancer
- 28:56Answers is provided by Smilow
- 28:57Cancer Hospital and AstraZeneca.