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Cancer Answers: Radiation Therapy for Cancer Treatment with guest Dr. Lynn Wilson, October 11, 2009

July 20, 2019
Dr. Lynn Wilson,Radiation Therapy for
Cancer Treatment October 11, 2009Welcome to Yale Cancer Center Answers with Drs. Ed Chu and
Francine Foss, I am Bruce Barber.  Dr. Chu is Deputy Director
and Chief of Medical Oncology at Yale Cancer Center and he is an
internationally recognized expert on colorectal cancer.  Dr.
Foss is a Professor of Medical Oncology and Dermatology and she is
an expert in the treatment of lymphomas.  If you would like to
join the conversation, you can contact the doctors directly. 
The address is and
the phone number is 1888-234-4YCC.  This evening Francine
welcomes Dr. Lynn Wilson.  Dr. Wilson is Professor, Clinical
Director, and Vice Chairman of Therapeutic Radiology at Yale School
of Medicine.Foss
 Can you tell us a little bit about radiation therapy and how it
differs from our common thoughts of radioactivity?Wilson
 Radiation therapy is something that's actually been used to treat
cancer patients for nearly a hundred years. There are several
different terms that mean the same thing; radiation therapy,
radiation oncology, or the department here at Yale which is
referred to as therapeutic radiology. These all really mean the
same thing, and radiation that we typically hear about on
television or in the public media may refer to things at power
plants or other unusual circumstances, but the kind of radiation
therapy that we do in medicine is very well regulated and
specifically targeted, in most cases, toward tumors or a
malignancy.  There are some situations where we use it to
treat noncancerous conditions, but it's very well focused and
treatment plans are very well designed, so that things are very
closely regulated.  It's much-much different when it's used in
medicine compared to other non-medicinal applications.Foss
 Can you give us a little history about the use of radiation
therapy in medicine?Wilson
 X-rays were discovered over 100 years ago, and things were fairly
rudimentary in the beginning because we weren't able to aim things
in a very particular direction, we were still learning about
it.  As things evolved over the years, technology has become
more advanced and we started to use what's called a linear
accelerator. A linear accelerator is what we know today as the
standard form of applying radiation to cancer patients.  The
linear accelerator is a device which accelerates an electron at
very high speeds down a short course that interacts with the
target, which produces a photon, or an X-ray, and that X-ray comes
out of the machine and can strike a tumor within a patient, and in
terms of the size of that X-ray or how energetic it is, or how deep
it goes into the patient can all be decided and regulated by the
 So the kinds of machines that you are using for radiation therapy
are very different then X-ray machines?Wilson
 Very different.  An X-ray machine basically sends an X-ray
out and goes through a patient3:05 into mp3 file
 and on the other side of the patient is the target, and it can
capture that image; that would be a diagnostic type of X-ray. All
of the radiation that I, or anyone in our department here at Yale
uses, or anyone who is doing radiation oncology, it would be used
for a therapeutic purpose as opposed to a diagnostic purpose.Foss
 There are a number of different ways that radiation therapy is
used, and I understand there are also radioactive elements that we
give to patients, could you talk a little bit about the types of
radiation therapy?Wilson
 Sure, there are three major types.  External radiation, which
we call teletherapy, is the kind of treatment that would come from
that linear accelerator, where a patient is on a table and the
beam, X-ray, or photon as we call it, comes out of the machine and
strikes the tumor within the patient.  That's the majority of
the type of radiation that's used to treat cancer patients. 
There is another form of treatment referred to as brachytherapy,
which is the use of radioactive sources that can come in several
different forms.  They can be very small seeds, in the case of
a prostate cancer implant for example, and brachytherapy refers to
the application of radioactive sources very close to the tumor, or
next to, or implanting the tumor.  A third form of therapy is
where we give a systemic, or an agent which can go completely
around the patient's body, perhaps in the blood circulation, and
there are radioactive isotopes that are attached to antibodies that
seek out certain malignant cells in the body. That's a systemic
form of radiotherapy, but the most common form that we use is the
linear accelerator.Foss
 We also use radiation elements in diagnostic testing in common
diagnostic testing in say thyroid cancer treatment, as well as in
MUGA scans that we do to look at heart function.Wilson
 That's a bit different, those are radioisotopes though, and they
are targeted to certain tissues.  In the case of thyroid
cancer, there are a couple of different things, you can have a
diagnostic scan which may show us the activity that's going on in a
particular thyroid tumor where its lighting up for example, as it
appears on the scan, and then there can be therapeutic uses in
thyroid cancer of radiation as well, but the primary type of
radiotherapy we use is teletherapy, its commonly referred to as
external beam and that could also be used in the thyroid, for
example.  We have these different choices that we can use and
it can get rather complicated, but that's why the
residency-training program is rigorous and fairly lengthy because
there is a lot to learn and there are a lot of different
applications and lot of different choices.Foss
 What kinds of cancer do you use radiation therapy for?5:45 into mp3 file          
 Almost all of them, and there are some that are a little more
radio-responsive than other types, but really all cancerous cells
will be responsive to radiation.  Some are exquisitely
responsive to radiation, and we would use just radiation alone, for
example, in the treatment of a patient with a certain type of
problem.  Other malignancies can be better treated by a
combination of radiation with systemic agents, or chemotherapies,
for example.  The answer is really most, or nearly all
malignancies will be sensitive to radiation.  The question is,
are they sensitive enough for us to use just radiation alone, or do
we need to combine that with another systemic or chemotherapy agent
to have a better chance of curing the patient?Foss
 Is radiation therapy used at the beginning as a first therapy for
cancer or is it used later, or both?Wilson
 Both.  Sometimes it's used as an initial or first therapy,
and then that would be followed by chemotherapy.  Today, since
we have moved toward personalized cancer therapy where we are
trying to target that patient or that type of cell directly with
very-very specialized treatment programs, and this falls into the
area of selected chemotherapies, we often combine radiation and
chemotherapy together for the best results. There are some
situations where we might give chemotherapy first in a patient with
lymphoma, for example which are many of your patients, and then we
might follow that with radiation which we refer to as consolidative
treatment, and the doses can be different.  Sometimes we use a
very high dose when it's used initially, but there are some
disorders where we use radiation alone and the doses are very low,
so it depends on cell type and the clinical situation, and that's
what makes this complicated. The answer to your question is really
all three, before, together, and perhaps after.Foss
 In fact, if you go really far back in time, one of the first
cancers that was cured with radiation therapy was Hodgkin's
 Even today radiation therapy is a main part of the therapy for
many lymphomas.Wilson
 That's right, and that's changed a bit as the systemic therapies
have become more advanced, new developments and better targeting,
and we also are better today at making the diagnosis, and learning
more about where these diseases might be harbored inside the
patients body.  Systemic therapy and radiation have both come
a long way over the last 40 to 50 years.Foss
 We have heard that term, radiation sensitizer, when we talk about
certain kinds of8:09 into mp3 file
 chemotherapy drugs, could you talk a little bit about that whole
concept of a radiation sensitizer and how often you employ that in
your treatment of patients?Wilson
 For example, in head and neck cancer there are some early stage
head and neck cancers that are very-very well treated with
radiation alone.  The tumors are very responsive and it's not
necessary to add anything to help that radiation do its job, but in
more advanced head and neck cancers, for example, we can use
relatively high doses of radiation to solve the problem but when we
get to certain dose levels we begin to get into a problem where the
side effects of the treatment become fairly significant. So over
many years we have introduced radiosensitizing drugs that make
these cells a bit more sensitive to the radiation so that we can
still use high doses of radiation, but don't need to push so hard
that patients get such bad side effects from the radiation that the
treatment essentially becomes worse than the disease.  What's
nice about cisplatin, for example, is it not only has activity by
itself against the cancer cells, but also has radiosensitizing
properties and can do things to those cancer cells that make them
more sensitive to radiation then they would be without the exposure
to a drug like cisplatin, and that's just one example, there are
 This touches on an important point that we often talk about on the
show, which is the multi-modality approach for many cancers. 
It sounds like with solid tumors in particular we have surgeons, a
radiation therapist, and a medical oncologist, could you talk a
little bit about the multidisciplinary approach and how it applies
to radiation oncology?Wilson
 The multi-modality or multidisciplinary concept is really-really
important for the patient for several reasons.  Here at Yale,
for example, the patient can come and be seen by multiple
specialists in one visit.  For example, in our practice you
may see the patient in the morning and then I will be seeing the
patient immediately afterwards, and we may have the patient see a
surgeon after that.  It's really one visit for the patient and
that helps with logistics.  The other advantage is that all of
the physicians and specialists that are involved will typically
meet perhaps later that day regarding the patient's that have all
been seen in this multidisciplinary consultation.  We review
all of the pathologies, all of the X-rays together, and we are
literally all together in the same room going over each patient's
case.  It really provides a high level of carefully
coordinated care for the patient so that everything is well
understood and we can reach a consensus, and it's really excellent
for the patient.  Now in a setting where that's not available,
certainly a patient could see a radiation oncologist, a medical
oncologist, and a surgeon, but the visits may be spread out over
several weeks and those physicians may not even work in the same
building as each other, so that can in a way cause some challenges
in communication and often that can work, but there is no better
substitute then to be able to see all of the physicians in one
visit and those physicians are11:10 into mp3 file
 actually working with each other, working together on that
patient's particular case that day and have accessed all of the
same information in real time.Foss
 These multidisciplinary clinics have only come about over the last
four to five years, prior to that we weren't really thinking in
those terms when we treated patient's with cancer.  Can you
talk a little about how the multi-modality approach applies say
after the patient is treated moving forward in the follow-up, do
you still see those patients?Wilson
 Yes, we do, and that's very important because as we have more
experience under about belt, so to speak, having patients as cancer
survivors and doing better and having better clinical outcomes, the
patients are always at risk for a couple of things.  One is
long term side effects from treatment, so we see them frequently
and observe them for conditions that may come up that are related
to the treatment so that we can intervene rapidly to try to help
with any problems or counsel the patient regarding these issues. Of
course there is also the issue that patients are doing better, more
patients are being cured the first time around from their cancer,
and with some malignancies patients are at risk to not only have
that malignancy come back again, but also may be at risk for a
second cancer that may come up, so we have to monitor them
carefully.  A head and neck cancer patient, for example, is at
an increased risk for lung cancer, typically if they have a smoking
history, and so we evaluate these patients in the follow-up as part
of a multidisciplinary program as well.  They don't always
have to be seen by all the physicians and we are sensitive to not
having a patient have inappropriate or unnecessary doctor
appointments, but we all follow patients very closely and they are
often seen in these multidisciplinary settings.  If there is a
problem or there is something new that's diagnosed, the value of
this is that we have all the consultants together so that we can
put our heads together immediately for that patient without
 Lynn, can you talk a little bit from a patient's point of view
about the logistics? Say a patient sees you and needs to get
radiation therapy, what happens next?Wilson
 There are a couple of options for that.  If it's someone who
has an emergent problem, for example, there is bleeding from a
tumor or they are very uncomfortable because of pain or they are
having a breathing problem from a lung cancer, in that situation, I
would be called to see the patient, and we would see the patient
immediately and start treatment very urgently, that day. 
That's one scenario, that's fairly unusual, but we are prepared to
manage that for the patient if it happened.  What typically
happens is we see the patient in a consultation, they will see
other specialists regarding the problem, typically that day, in a
multidisciplinary program here at Yale, and we would formulate a
treatment plan that day among the physicians for the patient. 
This will then be communicated to the patient from one or more of
those physicians, and with respect to radiation therapy, we would
then plan to have the13:57 into mp3 file
 patient come in for what's called simulation. That might happen
the next day, or several days later, and we take the patients
logistics into account as well.  We want to try to give them
appointments that work best for them.  During the simulation
process, that's really where the design of the radiation treatment
begins, and in our program that patient gets a specialized CAT
scan, although its an easy CAT scan because they generally don't
need to swallow any material or get an intravenous injection but
sometimes we do that, and we use those images from that scan to
carefully plan their radiation treatment which will then begin
within one to several days later as coordinated, depending on what
the multidisciplinary plan is.Foss
 Thank you Lynn.  I would like to talk a little more in detail
about some of the long-term effects of radiation when we come back
from the break.  You are listening to Yale Cancer Center
Answers and we are discussing radiation oncology with Dr. Lynn
 Welcome back to Yale Cancer Center Answers.  This is Dr.
Francine Foss and I am joined by Dr. Lynn Wilson, Professor of
Therapeutic Radiology at the Yale School of Medicine.  Lynn,
we have talked a little bit about the logistics of radiation
therapy with the simulation and the treatment planning.  Can
you tell us a little bit about the long-term complications and the
immediate complications of patients who are undergoing radiation
 Certainly, and managing those complications is critical to a
successful treatment program.  There is not one set of side
effects or complications that would happen for any one patient with
any kind of malignancy.  It really depends on what part of the
body the problem is in, sometimes the age of the patient and what
they can tolerate, what we call their performance status, and how
well they are doing before we start treatment. Some of the very
common side effects of radiation that we see in all patients are
some level of fatigue, although usually that's relatively minor, if
we are treating something in the head or brain area, we can see
hair loss.  Usually with any type of radiation it's from
external beam, so we will see some irritation of the skin, not
typically a sunburn type of effect, but some irritation or
perhaps16:47 into mp3 file
 dryness of the skin.  There are some treatments that we do,
for example gamma knife treatment, which is a very-very specialized
treatment that we have had at Yale for many-many years that we use
to treat brain tumors or metastatic lesions in the brain. That
technology is developed in such a way that treatment is given very
quickly and with extremely minimal side effects, and often even
without any hair loss.  If we are treating a problem in the
lung, sometimes patient's can get an irritated or sore throat, or
trouble swallowing. We spent a lot of time trying to design and customize these
treatment programs for each patient so that we can avoid these side
effects to the greatest extent possible.  Many years ago, when
we didn't have the kind of technology that we have now, because it
was not available at any centers, we would set up beams and aim
them at tumors, but it was very-very difficult for us to avoid very
critical structures such as the heart or the esophagus, and that
example you brought up of Hodgkin's disease many years ago when
radiation alone was used to treat Hodgkin's disease, it was a very
successful program, but the radiation fields were very large and
came with quite a bit of toxicity; now we can avoid that. But there
can be gastrointestinal side effects, in some cases, depending on
how much intestine or bowels are in the field, but these are things
we try to take into account. Most patients do very-very well and
can have a very-very minimal side effect profile.  Those are
the kinds of things that might happen during the treatment
course.  Longer term, sometimes patients can develop scar
tissue, but again we try to counteract that by deciding on what
sort of fractionation schedule, or how often the patient should
come for treatment.  If we give very large doses of radiation
over a very short time, just a couple of days, that patient is at a
slightly increased risk for long term complications of scarring, to
give one example, or fibrosis, or a complication in the
bowel.  Whereas if we gave treatment to the same area, but
spread it out over many visits, say a month, or five weeks, the
chance of having a longer term complication is really-really
minimized, and these are general recommendations, but these hold
true.  That gets us to the reason of how long it takes to give
radiation, and that's one of the main reasons that many of the
fractionation courses are quite long and spread out of over many
weeks, seven to eight weeks for example, nine weeks in some of the
lymphoma treatment that you and I work with when we use total skin
electron beam.  I could give enough radiation in several days
to probably manage the problem, but this long-term side effect
profile will be much higher.Foss
 That gets to an important point that I wanted to touch on, which
is the technology that is involved in radiation therapy.  I
have been down to your department, and I have been very impressed,
obviously, by the big machines, but also by the tremendous amount
of computer work and time that goes into planning these treatments,
it's a very complicated procedure?Wilson
 It's extremely complicated, 20 to 25 years ago we had these linear
accelerators so we had good technology, but much of it was more
driven by human beings, it wasn't nearly as19:51 into mp3 file
 computerized.  Still to this day we have radiation therapists
on staff who are right on site with the patient at the linear
accelerator at all times, and we have several of those staff
members present at all of our linear accelerators, but things have
become really technically advanced in the age of electronics and
this is good for two reasons.  One, we are able to deliver
radiation more precisely then we ever have been before through the
use of onboard imaging, and on our linear accelerators we actually
have the ability to do what's called a cone beam CT scan as part of
the treatment program, and that helps us to delineate that the
treatment field is going exactly where we want it to and to really
document.  Now, we are starting to take tumor motion into
account, but there is a tremendous amount of computer and
electronic capability and technology behind these treatments, but
the staff member, the actual human being, is also essential to
everything going well.Foss
 I have also heard about the use of PET imaging and other ways of
actually imaging a tumor so that you can more precisely delineate
the tumor.  Is this going to be part of the future in terms of
radiation therapy, using these kinds of labels or tags to precisely
isolate the tumor cells?Wilson
 Not only is it going to be a big part of the future, but we use it
now. To pick another example for lung cancer, every patient that we
evaluate at Yale who has lung cancer will be getting a PET
scan.  They have either had one before we meet with them, but
if not, we get it both for diagnostic purposes, and it's absolutely
essential in the treatment planning of their care. We don't want
just anatomic definition, we also want metabolic information, how
active is that tumor?  Sometimes the metabolic information for
a PET scan, for example, will give us additional information that's
useful in treatment planning compared to just a static CT scan
image, and also as part of imaging, every patient that would get
lung cancer treatment at Yale will have what's called a four
dimensional CAT scan, and that's a special CAT scan that actually
takes the motion of the tumor into account. That's important
because if we have a lung tumor, everyone is breathing, that tumor
is going to move, it may move a little bit in some patients, or it
may move quit a bit, several centimeters, or an inch or two in
other patients, and we need to take that motion into account. 
We are not interested in just setting up a radiation field that's
sort of big enough to just account for the motion, as might have
been the case many years ago before we had these kinds of
technologies, but now we take that into account, and again, it
gives us another advantage in being able to very precisely target
these tumors and account for that motion every single day while the
patient is undergoing treatment.Foss
 Sitting here as a person who does chemotherapy as a medical
oncologist, I feel as though what I am doing is fairly primitive,
because I inject a drug into a patient and I am not exactly22:35 into mp3 file
 sure where that drug is going to go.  It sounds like you have
a much better handle on being able to treat tumors effectively with
radiation therapy.Wilson
 We have done really well in terms of both how we devise the
treatment plans, IMRT, for example is a technique that has been
available at Yale since the mid to late 90s, where we use many-many
radiation beams that all converge on a single target and often
motion isn't so much involved with that problem, but its again a
way to deliver treatment that's in a highly precise manner so that
we can avoid side effects.  When we are treating a head and
neck cancer patient, for example, we would like to avoid the side
effects of a dry mouth. That may not sound like such a problem but
it's a major side effect in the treatment of head and neck cancer
and with the use of IMRT we can often completely avoid that problem
because we can exclude the parotid gland, the gland that makes our
saliva.  There are two of them and we can avoid them, or at
least one of them as part of our treatment program.  Even as
recently as in the mid 90s, we couldn't do that.  Those
parotid glands would get treated as part of the therapeutic package
and that added to patient side effects, but we are able to target
better, and we can deliver treatment more carefully with more
definition, and we can take tumor motion into account which we were
not able to do years ago. 4-D CT is a relatively new technology we
have at Yale and have been using it daily for several years now,
and then of course your point about the PET scan and bringing that
into the armamentarium. I am not talking about just having a PET
scan that we look at on a computer and say, there is the problem, I
kind of know where it is.  We actually take the PET scan
information electronically loaded into our computers and
superimpose those images over that four dimensional CT scan and
plan for that patient as an entire package, so that's the level of
detail that we are using when we are planning these cases for
 Can you talk a little bit about research and your particular
research interest?Wilson
 We are certainly well recognized as one of the most well funded
NIH research programs in radiation oncology in the United States,
and have been for many years.  There are several kinds of
research that go on in our department.  There is basic or
laboratory research that's happening, it doesn't involve patients,
where scientists are trying to make new discoveries relating to
perhaps radiation sensitizers, types of cell lines that can respond
to different kinds of radiation in new sorts of ways and all sorts
of basic laboratory research that's happening.  Another major
form of research that's happening in the department is clinical
research, where patients are part of clinical trials or clinical
investigations where we are trying to answer questions by looking
at patients that we have treated over many years and studying their
results, and we have a variety of clinical trials that are involved
that include the use of radiation, and many of them chemotherapy as
well, that are available to patients right now.25:28 into mp3 file
I know that Lynn, you are one of a very few number of radiation
therapists in the country that does a specialized kind of treatment
called total skin electron beam radiation, and that's specifically
for  patients with a rare disease called cutaneous T-cell
lymphoma, that I also study.  Could you comment a little bit
about that specialty?Wilson
 Total skin electron beam therapy is extremely complicated. 
It's one of the most complicated treatments that we do in all of
radiation oncology. The reason its complicated is because if you
can imagine all of our skin folds and the nooks and crannies, how
do we really get a good dose of radiation that's relatively as
equal as possible to every spot around the body in a way that's not
toxic for the patient or doesn't cause other problems for them
internally?  This is why it's complicated.  We are one of
the busiest centers literally in the world.  Many patients, as
you know, come to see you and I from other states, sometimes other
countries, and the total skin program has been in place for over 30
years at Yale.  The technology was initially developed at
Stanford University and then quickly was adopted here shortly
thereafter.  We have treated many-many patients with this
technology.  Everyday we have patients at Yale receiving total
skin electron beam therapy and so we have a really dedicated
program with therapists that know a lot about this particular kind
of treatment, and physicists who are involved in the calibration of
the machine doing certain measurements for each patient, and so
that's a highly-highly specialized kind of radiation that's not
given at many centers.  All centers are capable of doing it,
but its so technically complicated there are only probably a
handful of even academic centers in the United States that have
enough expertise in this to have the kind of volume, or that even
do more then ten cases a year.  We do many more than that.Foss
 This is a treatment that could be curative for these patients as
well.  Can you talk a little bit about your success for this
 That's right.  There are many different forms of the disease,
as you know, and there are different kinds of skin lymphoma. 
Radiation treatment is a highly successful treatment for these
patients.  All of these patients respond to radiation. 
It's a matter of who is going to have a complete response, and this
gets to the point of how we combine therapies.  Often we will
do radiation treatment, but sometimes that will be followed with
the systemic agent, or given concomitantly with the systemic agent,
or will follow it with another kind of therapy to maintain
reemission or cancer control for the patient, but patients do
very-very well with this treatment.  Certainly, the patients
with earlier stage disease do better then patients with more
advanced disease, but even those with very advanced disease, with
tumors on the skin or involvement of their blood with the disease,
there is a role for total skin electron beam therapy in certain
patients.  Since this treatment is so successful for these
folks that have, and28:18 into mp3 file
 have suffered with this problem for many years, that's one of the
reasons that we are a big referral center for this disease.Foss
 Lynn, I would like to say one thing about that and that is that a
lot of times people don't really appreciate the value of this kind
of treatment, even if it is palliative, even if the patient has a
recurrence of their disease.  These patients are so
symptomatic and they get better so quickly with total scan
radiation therapy.  I think its very valuable part of our
treatment and approach for these patients.Wilson
 I agree, and again, what's nice about our program is that the
treatment is literally skin-deep, or perhaps touches on the tissues
just below the skin surface.  Patients do not get an upset
stomach, they don't get breathing problems, and in fact they get
minimal fatigue, very low level fatigue if they even get it. 
Patients can drive, go about their social and professional routines
and the treatment is very-very safe. In fact, we don't even worry
about bone marrow toxicity or effects on the blood counts; we get
one blood count at the beginning of the therapy so that we have it
documented and we don't have any troubles.  It's well
tolerated and is an excellent palliative treatment.
 Thank you very much Lynn.  This has been a really fascinating
discussion about radiation therapy.  You have been listening
to Yale Cancer Center Answers, and I would like to thank my guest
Dr. Lynn Wilson for joining me this evening.  From Yale Cancer
Center this is Francine Foss wishing you a safe and happy week.If you have questions or would like to share your comments,
go to where you can also subscribe to our
podcast and find written transcripts of past programs.  I am
Bruce Barber and you are listening to the WNPR Health Forum from
Connecticut Public Radio.