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Cancer Answers: An Overview of Radiation Therapy, February 17, 2008

July 21, 2019
Dr. Lynn Wilson, An Overview of Radiation
Therapy February 17, 2008Welcome to Yale Cancer Center Answers with Drs. Ed Chu and
Ken Miller.  I am Bruce Barber.  Dr. Chu is Deputy
Director and Chief of Medical Oncology at Yale Cancer Center and
Dr. Miller is an oncologist specializing in pain and palliative
care.  If you would like to join the discussion, you can
contact the doctors directly.  The address is and
the phone number is 1-888-234-4YCC.  This evening, Dr. Chu is
joined by Dr. Lynn Wilson.  Dr. Wilson is a Professor, Vice
Chairman and Clinic Director of the Department of Therapeutic
Radiology at Yale School of Medicine and is here to discuss the use
of radiation therapy for cancer treatment.Chu
 Why don't we start off by discussing what radiation therapy
 Radiation therapy is the medical usage of radiation to treat
cancer patients.  There are some nonmalignant or noncancerous
indications that would require the use of radiation treatment, but
greater than 95% of the patients we treat have cancer of some
sort.  There are three different ways we provide radiation to
such patients, it can be a part of a definitive cure, and it can be
given adjuvantly, meaning after the primary treatment for a patient
who may have had surgery as their primary treatment; we often use
radiation after the surgical procedure. It can also be used in the
palliative setting where we are trying to help a patient get relief
from symptoms, whether it is bleeding or pain.Chu
 Let's hold off on that for a moment and start with the
basics.  When I think of radiation therapy, I think of some
machine focusing x-rays at a particular spot.  Is that
correct, or are there other ways of giving radiation therapy?Wilson
 There are several ways.  Thinking of the machine focusing on
a particular spot is really the primary modality, and that machine
is called a linear accelerator, which has been around for many
years.  Different generations of technology have improved our
ability to focus, but these machines actually generate electrons
that are accelerated several feet down a pathway at very-very high
speeds. They impact a tungsten target usually, and that produces a
photon, which is an x-ray that is aimed very precisely at the part
of the body that we are interested in treating. A photon is really
just a group of very energetic particles that can interact with
cellular DNA to damage cancer cells. When the beam comes out of
this linear accelerator device, it is highly focused and extremely
precise.  There are other ways of delivering radiation therapy
though. Brachytherapy is a term that refers to the implantation of
radioactive seeds, for example, to treat prostate cancer, cervical
cancer and a variety of other tumors. There are some relatively
new, systemically given agents, which have monoclonal antibodies
that are targeted at certain types of cells. Those have radioactive
molecules attached to them so that the radiation can be delivered
very, very specifically.Chu
 Are there any instances in which you might think of combining the
x-ray form of radiation therapy and the brachytherapy approach?3:24into mp3 file
 Yeah.  There are of a variety.  That is sometimes done
in prostate cancer.  Here at Yale, we have extensive
experience in brachytherapy and a variety of different organ
systems, particularly for GYN cancers and for head and neck
cancers, and quite often we combine brachytherapy, the implantation
of radioactive seeds into a tumor in the head and neck, with the
patient receiving external beam radiation as a part of their
treatment package. Chemotherapy is often an important part of that
combination as well.Chu
 Now what about this term Gamma Knife, how is that involved in
radiation therapy?Wilson
 Gamma Knife is a particular type of way to deliver radiation to a
very, very pinpoint precision-based target.  It is typically
used for treatment of brain tumors and it's an array of cobalt
sources that are radioactive that actually produced x-rays. Those
are focused at a particular point in the brain with many, many of
these sources converging on one very small pinpointed area. 
The advantage of something like Gamma Knife is that we can deliver
very, very precise high doses of radiation to small places in the
brain and minimize the amount of radiation to the other parts of
the brain, which is very important.Chu
 Is that the preferred approach for treating patients with brain
 Well, it depends.  It depends on the type of cancer and the
size of the cancer itself.  For some patients who have very,
very small primary brain tumors, it may be a reasonable
option.  It is certainly commonly used for patients where
their cancer has spread to the brain coming from the lung, for
example, or breast cancer where it has deposited itself into the
brain. It can be used very effectively to eradicate such
 When we started off the show, you mentioned that radiation therapy
can be used in three different settings. Let's get into that a
little bit more.Wilson
 Sure.  The primary setting that we use radiation for, and
most of the cases that are treated, are for definitive treatment.
What I mean by that is, taking something like prostate cancer for
example, surgery is obviously one option, but radiotherapy is
another, and it is a bit of a complicated discussion to decide who,
for example, would have the most benefit from surgery versus
radiation. But both of those modalities would be used to completely
eradicate the patient's cancer.  In our program here at Yale,
we use intensity modulated radiation therapy (IMRT) to treat all of
our prostate cancer patients. In lung cancer, for example, we would
use radiation perhaps in combination with chemotherapy for
definitive treatment with the intention of completely eradicating
the cancer. There are other examples, but those are the common
ones.  For a breast cancer patient, their primary treatment
might be surgery and they may have had a lumpectomy, we would then
provide radiation to that patient6:33into mp3 file to ensure that they have the best local control of
their cancer possible.  The palliative setting would be for a
patient who might have had a cancer spread to a bone, which can be
painful. We could provide a relatively short course of treatment
with radiation to alleviate their symptoms of pain.  Those are
the three primary settings.  It is a very important modality
in all three of those cases.Chu
 To further expand on the scenario you just mentioned in terms of
using radiation therapy for bone pain, we find that to be a very
effective way of relieving pain in most cases, almost instantly
from the moment you shine that beam on the particular area of bone
 It is extremely effective and what is nice about the palliative
treatment is often patients have courses of radiation that last 6
or 7 weeks, but in the palliative setting there are several
schedules that we can utilize.  We decide on how many sessions
are necessary based on the location in the body and how much soft
tissue may be intervening. We take all that into account, but
usually within a week or two, the patients can feel dramatic relief
from their discomfort, and as you suggest, sometimes it can be
appreciated after just one or two treatments, depending on the
cancer cell type.Chu
 One of the real advances that we have seen over the years is that
you are working in close concert with your other oncology
colleagues. Can you let our listeners know a little bit more about
that process?Wilson
 I am the primary radiation oncologist at Yale who works with the
Thoracic Oncology Program.  The patients that I typically see
have malignancies of the chest, most commonly lung cancer, and
there are three main advantages to what we call this
multidisciplinary approach here at Yale.  The primary one is
that it is very convenient for patients, because we have a variety
of different specialists; surgeons, medical oncologists and
radiation oncologists, all seeing the patient together.  Not
necessarily all in the same room at the same time, but perhaps
sequentially over an hour or two. It is really one-stop shopping
for the patient, which is great instead of having to spread those
appointments out over several weeks.  One primary advantage is
convenience.  Another advantage in our program, within the
department of radiation oncology at Yale, is that we have a variety
of different specialists and we have a very large group. By having
a large group, it affords us the opportunity to have one person
specialized in one or two diseases, as opposed to a very small
group where each physician would have to do a little bit of
everything.  With that we have tremendous expertise for each
one of our physicians.  When I have my clinical activity in
the thoracic oncology group, most of the patients that I take care
of have thoracic malignancies so I am able to specialize in that
clinically with my research efforts and so on.  The third
advantage for the patient in this multidisciplinary clinical
setting, is that since all of the physicians are together in
that9:55into mp3 file
 clinic, the patients get information with regards to
recommendations very rapidly instead of having to wait to see each
of the doctors over several weeks. We're actually discussing the
cases that day while the patient is there so that by the time the
patient leaves at the end of their visit, they have the
recommendations they need from all of the specialists who were
involved. There is convenience, expertise and the patient is ready
to embark on the treatment plan very efficiently and rapidly.Chu
 This is one of the hallmarks in advantages of so called designated
comprehensive cancer centers, where you have specialists from
different fields that have worked together to come up with a
well-integrated, coordinated treatment plan for the patient.Wilson
 That is right.Chu
 Obviously it is something that we focus on at the Cancer Center.
On average, how long are people treated with radiation therapy?Wilson
 It depends quite a bit on the clinical scenario, meaning the type
of cancer that the patient has and whether we are treating someone
with a curative approach, adjuvantly or palliatively.  We
talked a little bit about palliative treatment and that can be
given relatively quickly anywhere from say 1 to 10 treatment
visits.  Treating someone for prostate cancer definitively,
may take as many as 7 to 8 weeks. And that is daily treatment,
typically 5 days a week.  The treatment itself only takes 5
minutes or so and the patient is in our department only for about
20 minutes.  Once the visits in the treatment program are
underway, it is highly efficient and we try to make it as
convenient as possible for patients so that they can go about doing
their other activities, but generally, I would say the average
course of definitive radiation treatment is going to run somewhere
between 5 and 7 weeks on average, daily.Chu
 One of the real advantages of radiation therapy, as you say, is
that it is actually a very short period of time that the patient
needs to be in the clinic.Wilson
 An extremely short period of time.  Some of the very modern
and specialized treatments, such as Gamma Knife or stereotactic
radiosurgery, do take a little bit longer because there are many
beams being utilized to give highly focused radiation on one
particular spot. Sometimes those treatments tend to only be a
single treatment session, or they may be several. Although the day
may be longer, a patient who is getting stereotactic radiosurgery
may only have three treatment visits total. It may seem like a very
long time, but within a week or so over those three visits given
every other day, treatment is complete.12:51into mp3 file
 Before you begin the radiation treatments, there is very careful
planning that goes into deciding how to give it and what doses and
all of that.Wilson
 Absolutely, obviously delivering the treatment is critically
important, but the planning and the design of the treatment are
essential to have it done under the most modern standards with
great quality assurance.  We have an entire section within our
department called dosimetry, and have quite a few individuals whose
full-time position is to assist the physician staff with design of
safe and clinically appropriate treatment field design. 15-20 years
ago, we would typically treat a patient with maybe two beams, one
from the front and one from the back, to very large fields because
we did not have the diagnostic capabilities with high-quality CAT
scanning and MRI scanning as we do now, and we certainly did not
have PET scans back then.  We integrate all of this
information into the treatment planning for our patients so that we
can make it as accurate and as appropriate as possible. Those
planning sessions take quite a long time and typically a new
patient who comes to our department will have a consultation where
they meet with the physician, we take their history, of course we
would have reviewed the records prior to the visit, perform a
physical examination and spend a fair amount of time with the
patient and discuss the options and the treatment plan.  Once
we embark on an actual plan, the patient will come back for what we
call a radiation simulation; in our department that typically
involves getting a CAT scan. We use the information from that CAT
scan to start designing, with our dosimetry team, the appropriate
treatment fields, angles of the beams, how many beams to use, are
we are going to use IMRT? It is a complicated process that takes
many, many hours of work.  We also have a large cadre of PhD
level physicists who are in another section within our department
who are also involved in helping us do this treatment planning.
When that planning is complete and the physician has signed off on
the best plan and we are ready to go, the patient is contacted and
we make arrangements for them to come in and start the therapy.Chu
 Great, there is a very well coordinated team effort behind the
initial multidisciplinary team approach.Wilson
 That is right, and sometimes after that consultation we could
literally start the patient the next day.  In some cases that
are more complicated, say for example a very technically
complicated IMRT plan for the head and neck, that may take a week
or so before we are ready to actually start that patient's
treatment. That can be very disconcerting for patients, of course,
because everybody is anxious to get the treatment program underway,
but I cannot stress how essential it is to take the time and
integrate all of these expert team members into devising a
plan.  Another thing that we have not talked about yet is that
most of our treatments these days are highly coordinated with
physicians from your staff in medical oncology. We spend a lot of
time ensuring the coordination of radiation and chemotherapy on the
drugs and the doses of radiation that we use. These treatments
are16:05into mp3 file
 highly coordinated and not ad hoc in any way. It is important to
have radiation given after chemotherapy in some settings. There are
quite a few behind the scenes activities that go on after that
 At this point we would like to remind you to e-mail your questions
to, or
call 1-888-234-4YCC.  We are going to take a short break for
medical minute. Please stay tuned to learn more information about
radiation therapy with our special guest expert, Dr. Lynn
 Welcome back to Yale Cancer Center Answers.  This is Dr. Ed
Chu and I am here in the studio this evening with Dr. Lynn Wilson
talking about the use of radiation therapy for cancer
treatment.  Lynn, before the break you mentioned that
radiation therapy in some cases is combined with chemotherapy,
which obviously is in the realm of the medical oncologist, could
you tell our listeners what diseases you typically think about
combining radiation with chemotherapy for, and what might some of
the potential symptoms and side effects be.Wilson
 There are a variety of diseases where we do institute the
combination of chemotherapy and radiation. We often integrate
chemotherapy with radiation into the treatment package for very
locally advanced head and neck cancer.  The reason we do that
is because, although combining the two treatments sometimes can be
a little bit more toxic for patients, we know that the clinical
outcomes of local control, and in many cases the overall survival
of the patient, can be significantly enhanced.  Lung cancer is
another possible combination of said therapies. Not early stage
lung cancer, but in a stage III lung cancer for example, where the
patient has a tumor and lymph nodes in the middle of the chest that
we can see are involved by the cancer. This is all based on data,
not just based on what we think is best. It is based on many, many
years of clinical trials that have been completed. Our approach is
very19:10into mp3 file
 evidence based here at Yale. But lung cancer is another excellent
example where the best outcomes have been seen when we do a
combination of radiation and chemotherapy. Then of course there is
a whole other discussion that can be opened up about which are the
best drugs, what combination of drugs to use with the radiation,
what sort of schedule should we use, and there are various options
there. That is another advantage of the multidisciplinary team,
getting back to that.  We have these various schedules and
combinations I work with my colleague, Scott Gettinger, who is an
expert in medical oncology on the thoracic oncology team. Not only
is Scott an excellent clinical investigator and clinician, but he
is an expert at devising the treatment regimens for patients that
he thinks will drive the best clinical outcomes. It is obviously
important for patients to have a regimen that they can tolerate
 And I know that Scott in your group is trying to develop a
clinical study that combines some of these newer targeted therapies
with radiation therapy.Wilson
 Right.  Yes.  We are always trying to remain on the
cutting edge, and as I mentioned before, the basis for most of the
work that we do in the clinic today has directly come out of
clinical trial work that has been done, some clinical trial work
here at Yale, but also around the world. It serves as the basis for
what the best treatment for cancer is going to be in tomorrow's
 What are some short-term side effects of radiation therapy, either
alone or in combination with chemotherapy?Wilson
 They can be various.  It depends on the part of the body that
we are treating.  It depends on the radiation schedule and
what size radiation dose we are giving on a daily basis. Speaking
in general terms, the patients can have some fatigue from radiation
treatment.  Sometimes there can be some skin irritation. 
Generally when we do a combination therapy of radiation and
chemotherapy the side effects discussed can be a bit worse than
chemotherapy or radiation alone.  The whole concept behind
that dose is to try to be aggressive so that we can have the best
chance of curing the cancer or eradicating the problem.  So
fatigue, skin changes, decrease in blood counts, depending on how
much bone marrow we have to cover with the radiation field, some
irritation of the swallowing tube or the esophagus if we are
treating a tumor in the chest. That can come in the form of
discomfort on swallowing, or for a patient being treated for head
and neck cancer, a sore throat.  We know what to expect
because we have a lot of experience, and when we know to expect it,
we are in a better position to be prepared to counteract the side
effects. We counsel the patients on the first day regarding what to
expect and what might happen, and we are comprehensive about that
because I would much rather have a patient be prepared about all of
the potential possibilities as opposed to not having a thorough
discussion and then having something come up that they have never
heard of. That would cause a lot of anxiety.22:16into mp3 file
 One thing to emphasize to the listeners out there is that they
should feel free to ask any questions of their physicians.Wilson
 Absolutely, that is what we are there for.  In addition we
have an on-call service for our patients who are undergoing
treatment, and it is actually utilized by patient's who are no
longer in the treatment program. We provide that 24 hour and
weekend service to our patients.  This of course is especially
important for patient's who are on the active treatment program
now, who may be doing fine during the day, but develop a problem in
the middle of the night.Chu
 Lynn, is there anything that you can do for the fatigue issue?Wilson
 That is a tough one.  We do a lot of counseling right up
front regarding nutrition, exercise and curtailing certain
activities that we know will be strenuous for the patient during
the treatment course.  We try to predict what we can do, but
probably the best thing we can do is tailor the treatment as
accurately and specifically as possible to try to avoid as much
normal tissue as possible. But even through the use of very, very
small radiation fields, there is typically always some degree of
fatigue, although in most cases usually it is pretty minor.Chu
 And the skin rash or skin toxicity, is that like a sunburn?Wilson
 Well, it kind of feels and looks like a sunburn, it can be red,
itchy, irritating and sometimes uncomfortable for the patient, but
again, we are pretty good at predicting when we think this is going
to happen. There is not too much you can really do prophylactically
to prevent it, but there are a lot of things that we can do once it
happens in terms of certain emollient creams, soaks and different
schedules that we recommend to patients. It is different depending
on the part of the body or the size of the radiation field, but
getting back to the importance of the treatment planning, we take a
lot of care in designing these radiation treatment beams. 
When we use our computers and the simulation CAT scan, we can
actually see the dose distribution in the area of the tumor, and we
are looking at all the normal tissues as well. Evaluating the dose
of radiation to the skin is an important part of that quality
assurance package so we can try to minimize that sunburn effect,
because obviously that is very uncomfortable.Chu
 Are there any long-term consequences of radiation therapy?Wilson
 Unfortunately there are.  Some of the more common ones are
that sometimes there can be scar tissue formation. Long-term side
effects of radiation are almost directly proportional to the size
of radiation we give each day.  This is the reason for these
protracted fractionation or treatment courses that take many, many
weeks.  A common question I get from patients is, "Why do I
have to come for 724:57 into mp3 file
 weeks for the treatment, why can't we do this in a few
days?"  I could certainly give a dose of radiation say in 5
days, instead of 7 weeks, and that might be effective at
eradicating the cancer, but the problem with that is that there
might be tremendous long-term complications from that treatment in
terms of skin changes and scar tissue. If we were treating the
esophagus, scarring of the esophagus might cause long-term
swallowing problems, in treating a breast cancer patient, there
might be long-term scar tissue in the breast and the cosmetic
outcome may be very inferior compared to fractionating the
treatment over a longer period of time. The same holds true for
prostate cancer. Prostate treatment is one of our longer treatment
courses, but if we did the treatment very quickly, there might be
significant long-term bowel, rectum and bladder toxicity which
could lead to frequent urination, incontinence and those sorts of
 What type of clinical trials are you and your group here at Yale
doing for patients?Wilson
 We have a variety of clinical trials for various organ
systems.  We have two clinical trials for breast cancer
patients.  For one of them we are participating in a national
trial evaluating standard whole breast radiation versus only
treating part of the breast with radiation. That trial is ongoing
and our department participates in that trial. In fact, Dr. Joanne
Weidhaas is the principal investigator here at Yale and is the Yale
representative nationally running that trial. We are one of the top
accruers nationally to that trial, so we are extremely vested in
trying to answer the question of, is there an
advantage to partial breast radiation?  MammoSite, a term
patients or our listeners have probably heard, is one option for
partial breast treatment.  There is also a phase II MammoSite
trial, which Dr. Weidhaas designed, which is also ongoing and open
at Yale.Chu
 Any other trials?Wilson
 There are several others.  We have a head and neck trial in
combination with chemotherapy, from your colleagues, for patients
with very advanced head and neck cancers. We participate in an RTOG
trial, which is the radiation therapy oncology group, for patients
with stage III lung cancer investigating higher doses of radiation
with chemotherapy followed by surgery.  We have a vested
interest in that, and there is also a cervix trial for patients
with cervix cancer in combination with chemotherapy.  We have
a variety of trials and a variety of different organ systems,
specifically lung cancer, breast cancer, head and neck cancer, and
cervical cancer.Chu
 Great.  Lynn, it has been great having you on this
show.  The time has flown by. We look forward to having you on
a future show to hear more about what is going on in the Radiation
Oncology Group here at the Yale Cancer Center.27:46 into mp3 file
 Thank you very much.Chu
 Until next week, this is Dr. Ed Chu from the Yale Cancer Center
wishing you a safe and healthy week.If you have questions, comments, or would like to subscribe
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expert on cervical cancer.