coming up on mayo clinic q a the liquid
biopsy just means you're getting
information like you would from any
biopsy from some form of liquid
so that liquid can be blood it can be
urine or in our case we perform it on
the spinal fluid a spinal fluid biopsy
is a straightforward procedure that is
now used to detect the metastatic
progression of cancer cells and can help
determine the treatment plan
essentially you're sampling that fluid
to find out are there cancer cells there
what they are what do they look like
welcome everyone to mayo clinic q a i'm
your host dr helena gazelka
when cancer spreads from its original
location to other parts of the body we
say that it is metastasized
central nervous system metastases occur
when cancer cells spread to the brain
and the spinal cord
treatment for cns tumors can help ease
symptoms slow tumor growth and extend
life in order to determine which
treatment might work best for a person's
tumor type
some healthcare professionals are now
using liquid biopsies here to discuss is
mayo clinic neurologist dr wendy sherman
thanks for being here today wendy yeah
thank you for having me what an
interesting topic
uh first of all can you tell us wendy
what causes cancer to metastasize or to
spread from other areas in the body to
the brain and the spinal cord
no it's a good question and i'll and
i'll tell you that you know there are
there are multiple different ways that
cancer cells can reach the brain in the
spinal cord um you know it can enter
through the bloodstream or through the
lymph nodes
or sometimes even if it is in the bones
of the spine
because the spine is right next to
the spinal fluid and to the spinal cord
it can invade through there and enter
that way so there's a few different few
different ways they can sneak in
is it possible that any type of cancer
at all can spread to the central nervous
system or cns as we call it
it is possible but there are some
players that are much more likely to go
there you know the three most common
ones we see are lung cancer breast
cancer and melanoma those are the um by
far the most common that we see but but
we've honestly have seen all kinds
spread there though the other kinds are
much rarer
so let's get to the topic of the day
what is a liquid biopsy
it's a good question so and and it can
apply to different things so you know
really liquid biopsy just means you're
getting information like you would from
any biopsy
from some form of liquid
so that liquid can be blood it can be
urine or in our case we we perform it on
the spinal fluid so that's the fluid
that coats the brain in the spinal cord
and so
essentially you're sampling that fluid
to find out
you know what what cancer are there
cancer cells there what they are what do
they look like
you know what mutations do they have so
we're trying to get as much information
just like you would if you had a brain
biopsy and were to take out that piece
of the tumor and look at it under a mice
microscope and send it for testing same
kind of thing just off of off of fluid
well but that brings up a good question
then you lead right into my next
question when would someone decide to
use a liquid biopsy instead of doing um
a surgical
um or tissue type of biopsy
sure so and you know in our case
specifically within
the neuro-oncology field we use it on
the spinal fluid
most commonly when we're worried that
there are cancer cells in the spinal
fluid so someone can have cancer cells
in the brain or the spinal cord and not
necessarily be floating around in the
fluid but if it is in the fluid that's
very difficult to get by biopsy
you know people can try to biopsy the
the meninges or the lining
of the sac that holds the fluid
but that can be a very difficult biopsy
too and often can be inconclusive so
if we if we suspect that the cancer
cells are in the fluid that's the right
time to do this test
okay so you might have just answered my
next question then
which is
can you use this for any type of tumor
so currently yeah no i mean that and
that's a that's a question because
there there are there's testing
available currently
for specific cancer types
so for for breast cancer and lung cancer
and gi cancers gastrointestinal cancers
like stomach cancer and such
in more in the research field
that's being looked at for other cancer
types so it could still be done for
other cancer
types but that's still for research
purposes and and for
you know the care of the patient in the
clinic those are the primary cancer
types that we can look for
i can see one very obvious benefit to
patients and that it is simple to
receive to remove cerebral spinal fluid
it might sound awful to patients but
it's common very commonly done in a
fairly
straightforward procedure but do you see
um improvement in outcomes for
individuals who have
cerebral spinal metastasis and have a
liquid biopsy versus a tissue
i absolutely do and i'll tell you you
know in our day and age of treating
cancer it's no longer one size fits all
right so we have excellent drugs for
different cancer types that are really
based off of your specific
cancer so not just your lung cancer but
does your lung cancer have a specific
mutation
and there are drugs that match up to the
mutation that have been very effective
and the tricky thing is that if someone
has a cancer and they'll say in their
lung
and they have a mutation
let's just say an egfr mutation that's a
common mutation that a lung cancer can
have
we know that
upwards of 50 percent of the time when
that cancer travels to somewhere else
particularly in the brain
it can change
meaning it may lose that mutation so if
you treat someone based off of that
information
you know that you had a couple years ago
from where the cancer started that may
not reflect
you know the current state of your
cancer and what it looks like and so our
treatment really depends on that
and with with a lot of these new
generation treatments that are going
after these mutations
it has been very beneficial to look for
those in the spinal fluid and it it
absolutely i would say has extended
how people do with this and and both
from a symptom standpoint because we're
able to give them
often drugs that are better tolerated
because they're more targeted
and also it seems to extend survival
that is really interesting wendy i'm
sure that many of us have never thought
about the fact that a tumor cell that
came from our original tumor and is now
somewhere else in the body isn't exactly
the same cell necessarily
true and and i think it's increasingly
being recognized
you know another example would be you
know a breast cancer people talk about
her2 positive breast cancer and there
are drugs that match up to that her too
and we can actually inject those her2
drugs into the spinal fluid if the
cancer cells are in the spinal fluid and
so it's all the more important to know
once it's in the spinal fluid is that
her2 there or not and it can change
we've all seen it
so there must be limitations what are
some of the limitations of using liquid
biopsy when you're wanting to treat
metastases
well so it is still a newer test so you
know where we commonly prior to having
this test we had cytology and what
cytology means is when you sample the
fluid it tells us
yes we see cancer cells or not it
doesn't tell you how many cancer cells
or what their mutations are so we still
do run that test
the this new test we're doing is a lot
more specific so we do get a number of
cancer cells and like i said you know we
do get the the genomics of it too or
what mutations it has
um but we're learning we're learning and
i think
um you know for example we've all had
patients where
maybe the cytology results in this test
don't always line up and so we're
studying those cases so we can
understand how to incorporate both
both sets of tests or both data points
but it's you know it's a test that we
can draw while we're we're sampling
fluid anyways so
you know for example in patients who are
getting treatments in their fluid
while we give them the treatment we can
pull fluid at the same time and send for
this test so you're right in that it's
it's a relatively you know
low invasive um
low level of invasiveness when we do
this test and i think just as as we
continue to do the test and we do
research to another cancer types we're
going to learn more about how we can
apply it and how sensitive it is
well speaking of that is mayo clinic
doing research on the use of liquid
biopsy so we are um and it's it's
exciting because you know we want to
learn more about the use of liquid
biopsy you know particularly as it
pertains to to spinal fluid for not just
our brain metastases but also for our
our cancers that start in the brain so
the ones that don't travel from other
organs and we're not there with that
test yet
but we're looking we're looking at that
um and then also can we use other other
fluids in the body you know like i said
urine blood those samples are being
collected and tested so that hopefully
we can make progress towards that
wendy how widely available is this test
for patients who may not be at a mayo
clinic but are listening elsewhere
so as long as it's for those approved
indications like the breast cancer lung
cancer and gi cancer it's a commercially
available test that insurance is most
insurances do seem to be covering
so this is something that you could
request
you know from your from your physician
outside of mayo clinic
but also here at mayo clinic you know we
routinely do this and are
you know happy happy to do that as well
well thank you so much for being here
today wendy this has been a fascinating
conversation
yeah thank you for having me
our thanks to mayo clinic neurologist dr
wendy sherman for being here today to
talk to us about how liquid biopsy is
being used to treat metastasis
into the cerebral spinal fluid
i hope that you learned something i know
that i did and we wish each of you a
wonderful day
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