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Thanks for everybody
joining us today.
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I've been tasked with trying
to cover as much as I can
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about radiation oncology in
a nutshell in 10 minutes.
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Thankfully, I think a few things
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have been covered as
we've been going.
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But just as a brief intro,
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so radiation sounds scary.
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I think it like conjures up
like visions of The Hulk,
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getting superpowers
and stuff like that.
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But about half of
cancer patients
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will receive radiotherapy
as part of their care,
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and it's part of the
curative treatment
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for a number of
different cancers.
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It can be used in
conjunction with
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surgery or various
systemic therapies,
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often in the case in
prostate cancer with ADT.
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Now, I don't have fancy DNA
diagrams like John did,
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but radiation essentially
works by causing DNA damage.
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Diagrammatically, the
photon hits like a particle
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and basically spurs
on different types
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of actions that can damage DNA.
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We take advantage of biology
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when we deliver
radiation therapy.
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Normal tissues can repair
this type of DNA damage.
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Then cancer cells are
a little bit dumber.
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They are programmed
to grow, replicate.
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They lack the ability to repair
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their DNA in the same way
as your healthy tissues do.
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The other piece that we
leverage in radiation
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that I'll talk about
as well is spatial.
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Geometrically, we're able to
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target radiation in
very specific areas,
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and that helps us mitigate
side effects that are
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generated by DNA damage
to healthy tissues.
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Radiation plays a role in
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the prostate cancer care
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spectrum across a number
of different settings.
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This session, of
course, is focused
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on localized prostate cancer.
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In which case, radiation,
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its role is largely both
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definitive as an
option up front,
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but also after surgery as
doctor operberg mentioned.
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It also plays a role
in other areas.
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It's no positive
prostate cancer.
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We'll talk a little
bit about the
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oligometastatic setting later on
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today as well as in
polymeta prostate cancer.
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When we meet with patients,
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it's often a complex
decision making process.
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As a number of speakers
have discussed earlier,
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we really participate in
the shared decision making.
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I think our job is to review
the data that surrounds
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our treatments and try
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to equip you guys
with the knowledge to
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make a calculated decision
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and how to proceed
with your care.
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There are a couple
of main key factors
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that play a role in
our conversations.
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The first of these is to talk
about risk stratification,
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which doctor Washington,
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doctor She covered
earlier today,
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to think about each
individual patient and all of
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the specific aspects about
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everyone that we
should be considering,
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and then form a framework
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for the radiation
therapy options,
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as well as the hormone
therapy options
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for any specific individual.
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At that point, I think that
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the decision takes
into consideration
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the different preferences
and trying to handle
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the cost benefit decision
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across any of the
treatment options.
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Then, certainly we work
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closely with our
colleagues across
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the multiple disciplines
to come up with
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final decisions and to
help counsel folks.
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Then we proceed with treatment.
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Then I think doctor
Washington mentioned earlier,
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extensive follow up and close
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surveillance after
treatments for
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both outcomes and toxicities.
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This is diagramatically,
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all of a number of
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the different types
of radiation therapy,
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which we can't cover
everything in 10 minutes.
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But I think we'll hear
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a little bit about
radionucleides later in the day.
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I'm focusing a
little bit more on
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the therapeutic radiation
oncology options.
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The primary big groups,
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our external beam
radiation therapy,
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as well as brachytherapy.
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Brachytherapy is the way
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I describe it to folks
is internal radiation.
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There are a couple of ways
to deliver brachytherapy,
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both with permanent
implanted seeds,
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as well as temporary seeds
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that are placed via a catheter.
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We'll focus most of
our attention today on
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the pipeline or the
process and workflow.
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Through the external
beam radiation approach.
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We split external beam radiation
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frequently referred
to as IMRT or VMAT.
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Those are things
you'll find on Google,
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into three main sections.
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Historically, conventional
fractionation has
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been the mainstay in
external beam radiation.
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That's treatment that
goes over the course of
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up to nine weeks with
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radiation given daily from
Monday through Friday.
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Over the past couple of decades,
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there's been a trend towards
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what we call moderate
hypofractionation.
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The natural question
when patients
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were undergoing nine
weeks of radiation was,
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can you guys do this stuff
a little bit faster?
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A number of trials showed that
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we could feasibly do so with
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similar cure rates and
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toxicity rates with
quicker treatments,
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usually spanning
over the course of
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about four to 5.5 weeks.
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Then on the newer side,
past couple of decades,
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there's been a lot of
interest in what we call
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stereotactic body
radiation therapy, SPRT.
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SPRT has been used
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in a number of different
types of cancers,
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brain cancers, lung
cancers included,
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and certainly prostate cancer.
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SPRT is typically defined
as high doses of radiation.
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That are given over
fewer treatments,
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usually about five treatments or
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less and certainly has
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been used for
prostate cancer now
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for a couple of decades.
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Then I should mention
combination radiotherapy.
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Folks often hear about a boost.
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That's done with
a combination of
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extranal beam radiation
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typically done
conventionally fractionated,
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so about for five weeks,
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and then with a
boost that's done
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using either
brachiotherapy or SPRT.
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All right, so to give
you guys a little bit
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of diagramatic representation,
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this is just a
couple of examples.
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As you'll see online, that
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there are different ways
to deliver radiation.
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The current state of the
art is what we call IMRT.
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As you can imagine, back,
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before we did radiation plans
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were done with what
we call 3D conformal,
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and 3D plans, I
like to joke that,
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doctors aren't
terribly creative.
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The radiation beams basically
came from four directions,
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one beam in the front,
one beam in the back,
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and then two beams
from either side.
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As you can imagine, that
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resulted in more radiation
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being delivered to
healthy tissues.
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Then, over the past few decades,
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there's been adoption
of what we call
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intensity-modulated radiation
therapy, which is IMRT,
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and IMRT delivers radiation
from multiple directions,
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and the radiation beam actually
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changes shape as that
beam is delivered,
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hence the
intensity-modulated part.
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I'll actually show a
cool figure of that.
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Then VMAT is Volumetric
Modulated Arc Therapy.
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It's an iteration on IMRT,
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and typically what
we use here at UCSF.
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VMAT basically consists of
IMRT that's delivered over
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continuous beams that come
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around as the machine is
rotating around a patient,
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so it allows us to have a
smoother dose distribution,
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as you can see, in comparison
to the other options.
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When we meet with folks, this is
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the care path that
we go through.
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We have the consultation,
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and then when we're moving
forward through radiation,
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there are a number of paths
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or steps that folks go through.
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Then we'll talk a
little bit about
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the different pieces
of this care path,
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and then the different
aspects that
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happen when someone goes
through radiation treatment.
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The first step is once we've
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decided to do radiation
for localized disease,
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gold seed markers, placed by
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urology colleagues are
frequently the first stop.
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We then proceed with what
we call a simulation.
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I like to use the phrase
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radiation planning scan
because it makes more sense.
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Simulation comes from a
process that we used to do
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in older radiation approaches.
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That consists of a CT scan
with or without an MRI.
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We really use that
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scan to plan out the
radiation on the computer.
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We trace where the
radiation needs to go,
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and this is done on the
sub-millimeter level.
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Then we also trace
out and model out
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the normal organs to
make sure that we're
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avoiding those areas when we
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plan out the radiation
on the computer.
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We also develop
immobilization devices
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at this point in time,
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and then a couple
of setup things,
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bladder filling to help push
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the bladder farther away from
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the prostate and therefore
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further away from the radiation,
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and then having an empty rectum,
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which keeps the rectum flat,
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farther away from the
prostate, as well,
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both of those things to
mitigate side effects.
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Once we put that scan together,
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we work on it on the computer.
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It is probably the
most exciting picture
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of a doctor working on the
computer that I could find.
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But we put the images together,
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do all the delineation,
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and then come up with
a radiation plan that
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looks a weather map where
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the radiation is
focused on the target,
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in this case, on the prostate in
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this picture down
here, that's in red.
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Then it basically shows
the lower dose radiation,
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they're going to things
that are further
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out from the prostate.
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It goes to our medical
physics team after that,
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and they actually test
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the machine to make
sure that what we
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program in the computer
actually works in real life.
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Sometimes that doesn't happen.
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We test everything for safety
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before we start giving
radiation to patients.
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[NOISE] Then folks come in
for treatment each day.
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This is just a picture of one
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of the immobilization devices.
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It's basically a
glorified bean bag
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that we suck the air out of,
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and it forms the
shape of your back.
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That allows us to
plan radiation to
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sub-five millimeter
precision just
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to keep patients in the
same place each day.
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Then the radiation
machine spins around.
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People don't see you here,
taste the radiation.
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No one glows in the dark,
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no superpowers, or
anything like that.
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It really feels like getting
a scan done each day.
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Part of the treatment process is
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this alignment with
the gold seed markers.
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This is just an image of
what it looks like on
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the scans that we do on
board the machine each day.
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There's an automatic
process that allows
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the markers to be
matched on the machine.
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Then we also can manually make
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tweaks just to make sure
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that everything's
perfectly aligned.
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The scanners on the
machine up here,
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also show you the
bladder and the rectum,
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and so we can make sure
that those normal organs
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are appropriately
out of the way of
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the radiation to
mitigate side effects.
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Then the radiation
beam turns on,
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and it does change
shape like that,
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as I've had some patients who
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are brave enough to look
into the machine while
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it's running and delivers
the radiation each day.
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Then we see each other
routinely from there on out.
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Our surveillance process usually
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consists of having PSA checks
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every three months and then
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being stuck talking to me
every six months, at least.
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We manage a number of
different side effects
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during radiation.
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In the short term, these are
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side effects that happen
during the radiation and can
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last roughly about a peak
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about a week and a half or
so after the radiation,
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and start to basically resolve
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at about a month or so
after the radiation.
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These things are fatigue,
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and then things that are
related to areas that are close
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to the prostate so urine
and bell side effects.
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They usually kick in
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about halfway through
the radiation course.
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For more fractionated
radiation courses,
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is about three weeks or so in.
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When we do SBRT and
five treatments,
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usually about the second half
of the treatment course.
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Then long-term side effects,
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I think is one of
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the most important things
to consider as folks,
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especially are making decisions
about their treatment,
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and split them into
their domains.
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They're roughly the similar
areas, as with surgery,
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with the exception
of bell toxicity
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because the rectum sits
behind the radiation.
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One of the main things
I talk to folks
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about is the risk
of having blood in
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their stool even years
after radiation.
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For instance, that risk plateau
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is at about seven years out,
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which is quite sometime
after radiation.
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But these are the general areas
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of side effects
that we're keeping
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eye on as we follow
folks in the long term.
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With that, I think
I can wind down.
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I should give a
special shout-out
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to one of my colleagues,
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Osama Muhammad, who
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prepped some of the slides
that we used today.
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What is the question
specifically?
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Do we use SpaceOAR? Some folks
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have heard about
Erectile SpaceOAR.
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There are a couple of brands,
but the SpaceOAR which is
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a bioabsorbable hydrogel that
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is placed between the
prostate and the rectum.
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We do use SpaceOAR
here specifically
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in our stereotactic
or SBRT cases,
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so those short
courses of radiation.
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That's the main
place that we use
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them due to the data around it.
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It helps prevent and reduce
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that rectal risk that I
was talking about earlier.
