00:01
What about radiation therapy?
How do we think about radiation
that second type of treatment
for brain metastasis?
Well, I'd like for you
to think about
three types of radiation therapy.
00:11
The first is
stereotactic radiosurgery.
00:13
This is high dose of
extremely focused radiation
given to one or several areas
of the brain.
00:19
It has some names.
Gamma knife or cyberknife,
which are just other words that mean
stereotactic radiosurgery.
00:25
Its focal.
00:26
It's a high dose delivered to one
or several fossa in the brain.
00:31
It's really good efficacious,
and it has limited toxicity.
00:34
But there is a high rate
of recurrence outside
of where the radiation
is delivered,
because it's only delivered
to the area
where the high dose of radiation
is treated.
00:43
The second type of radiation
that I like for you to know
is partial brain radiation.
00:48
This is called intensity-modulated
or conformal radiation.
00:52
We're just a part of the brain
is treated with radiation.
00:55
There is maximal treatment
to the area of the tumor,
and then some treatment
that's delivered
to the margin around the tumor
that could give rise to recurrence.
01:03
We don't treat the whole brain
and so there's less
cognitive risk with that.
01:06
But we do treat a larger area
to prevent recurrence
into surrounding areas
around the tumor.
01:12
The last type of radiation
is whole brain radiation,
where we treat
the whole brain.
01:18
This is one of the
oldest forms of radiation,
and it's really
good for patients
who have many metastases,
or many tumors on the brain,
like the patient in our case.
01:30
So let's go through each of those
types of radiation therapy
and see and understand
a little more about them.
01:35
Here we see a good example
of the treatment field
for stereotactic radiosurgery.
01:40
You can see the colored images
on this slide
show where the radiation
is delivered.
01:45
The high doses
of radiation are red,
and there is very quick fall off
or drop of that dose.
01:51
As we go to areas around
where that metastasis is.
01:54
We can treat the metastasis
very well and very specifically.
01:58
And this is a great treatment
for focal brain metastases,
for a small number, or a
limited number of brain metastases,
and preserves patient's
quality of life and neurocognition
because a lot of the brain
is not receiving radiation.
02:13
There are some advantages
and some disadvantages
to stereotactic radiosurgery.
02:17
It effectively treats the disease
that we can see on the MRI,
but it doesn't treat
microscopic disease
that could be
elsewhere in the brain,
and give rise
to subsequent metastases.
02:27
We avoid
neurocognitive dysfunction,
but we give a high dose
to a certain area of the brain
and we can see necrosis in the brain
that can be challenging to treat,
and cause swelling and inflammation
around that area of metastasis.
02:41
<inaudible>
Stereotactic radiosurgery
can be delivered on a single day
really quickly, and avoids
delays to systemic treatment,
and more intense planning.
02:51
And we're able to retreat areas
or treat new areas of the brain
with stereotactic radiosurgery
which is not possible
with other types of radiation.
02:59
What about partial brain radiation?
This we also called
intensity-modulated
radiation therapy.
03:05
This is where a part of the brain
is treated with radiation.
03:08
You can see it here
in this treatment planning slide.
03:11
Again, the area of red is where the
high dose of radiation is delivered
up to mini gray radiation
is measured in gray
with a gradual fall off
to a margin around the tumor.
03:22
And you can see that here
in the right side of that slide.
03:24
Again, a high dose
of radiation delivered
to a large area of the brain
to cover both the tumor
and the margin around it.
03:33
And the last type of radiation is
Whole-brain radiation therapy.
03:36
And we can see
a treatment plan for treating
the whole brain with radiation.
03:41
This is favorable
and good for patients
who have too many
brain metastases
to effectively treat them
with stereotactic radiosurgery,
when we're worried about subsequent
decline in quality of life
or neurocognition
because the whole brain is treated.
03:54
And there is a high risk for
neurocognitive dysfunction
after this treatment.
03:59
And it's avoided when possible
due to side effects.
04:03
Here we see an example of
a whole brain radiation field
where we spared
the hippocampal.
04:08
Hippocampal or
the areas of the brain
that are important in contributing
to new memory function.
04:14
And our field is exploring
new ways to give radiation
that will treat the metastasis,
but not lead to
neurocognitive dysfunction.
04:21
And a good example of that here.
04:23
So when we do
Whole-Brain Radiation Therapy?
Well, for tumors that
are likely to metastasize
widely throughout the brain,
like small cell lung cancer,
when many metastases exist
more than 15 metastases.
04:35
Patients who have progressed
in the CSF space,
where we need to
treat all of the brain
and the multiple compartments
around it,
and for rapidly progressive
brain tumors.
04:46
Relative contraindications
or reasons not to think about
whole-brain radiation therapy
as if we've radiated
the brain before
and multiple rounds of
whole brain radiation therapy
are not possible
to the high risk.
04:57
Cancers that can be targeted
with a systemic agent
into systemic chemotherapy.
05:02
Patients who have
a low life expectancy
or innumerable systemic metastases,
which are likely to become
problematic, or result in death,
and severe impairment
in neurologic function
obtundation without
improvement with corticosteroids.