when most people hear the word cancer
they usually think of a tumor so they
think of a group of cells that are
dividing really rapidly that eventually
form a mass and you can see that mess
you can point to it and say that's a
source of our problem we need to get rid
of it right away either with surgery or
with medicine and I think what makes
leukemia harder to understand and harder
to visualize than other types of cancers
is the fact that with leukemia you don't
necessarily see a tumor and that's
because leukemia is a cancer to cancer
of the blood specifically to cancer of
blood cells so what are these cells
these blood cells that I'm talking about
well let's draw a blood vessel which is
where all of the blood is contained and
when most people think of blood they
they think of a liquid so that's what
I'm shading in the liquid part of the
blood but blood has lots of cells in it
too so for one it has these cells called
red blood cells and and hopefully you
can see that which are really important
for carrying oxygen and oxygen is
required by all of the organs in our
blood everything from your brain to your
muscles require oxygen and then there
are these cells that are called
platelets which actually aren't cells at
all they're little chunks or fragments
of cells that form blood clots to help
stop bleeding and then you have these
guys there are several different types
of white blood cells which is what our
body uses to fight off infection so
these are the guys that protect us from
bacteria and viruses and parasites so
these cells are found in the blood
that's why they're called blood cells
but they're actually not made in the
blood they're made inside the bone so
I'm going to draw a bone and if you were
to look at the boy if you were to look
inside the bone so if you were to take a
slice of bone like this and you were to
look at it so this is your eye right
here looking inside the bone you'd see
something like this you'd see that on
the outside of the bone is this hard
part that we all know about but that UT
that bone isn't solid all throughout
there's actually this hollow cavity in
the center of the bone and that hollow
cavity is filled with this red spongy
tissue
and that red spongy tissue is called
bone marrow and bone marrow is where all
of these different blood cells are made
so I'm going to clear that out so so
that we can see what bone marrow looks
like what's going on inside bone marrow
if you looked inside you'd see red blood
cells being made you'd see some cells
making platelets and you'd see white
blood cells being made right and this is
normal this is all completely normal but
in leukemia one of these cells it could
be a red blood cell a platelet or white
blood cell starts multiplying really
rapidly and out of control and it starts
over taking the bone marrow kind of kind
of like this and that's a problem for
two reasons firstly this cell that's
dividing really rapidly this leukemia
cell doesn't serve any function like a
normal blood cell does so it doesn't
carry oxygen it doesn't fight off
infection or help make blood clot it
kind of does nothing it's kind of a
waste of space and that's a problem
because we don't want to use any of our
body's energy making cells that don't
help the body right and secondly it's a
problem because if any one cell starts
dividing really rapidly and taking up a
lot of space inside the bone marrow that
leaves behind very little space and very
little food for the other cells to grow
so because of this the bone marrow isn't
able to make as many of those other
normal healthy blood cells and if it
can't make them then it can't supply
them into the blood and that's the
problem you see with leukemia where you
start seeing fewer red blood cells in
the blood that's those guys and fewer
platelets and fewer white blood cells in
the blood and then eventually when the
leukemia cells run out of space to grow
inside the bone marrow they leak into
the blood so you start to see leukemia
cells in the blood kind of like that and
actually this picture right here
explains almost all of the symptoms that
you see in leukemia so let's make some
room to talk about the symptoms of
leukemia symptoms okay so firstly we
said we see a decrease
the number of red blood cells right
which I'm just going to abbreviate as
RBC's for red blood cells and since red
blood cells carry oxygen this leads to
symptoms like weakness and tiredness and
fatigue and the fatigue is from the
brain not getting enough oxygen and the
body compensates for this by starting to
breathe more quickly so the patients
start to experience some shortness of
breath and because red blood cells give
the blood it's red color the patient
starts looking paler when they have
fewer red blood cells we also said that
we see a decrease in the number of
platelets in leukemia so if the patient
starts bleeding for whatever reason they
don't have enough platelets around to
form that blood clot that stops the
bleeding
so they experience prolonged bleeding
and they also see bruising easy bruising
okay and finally we said that there's
fewer white blood cells which I'm just
going to abbreviate as WBC's right and
since white blood cells help fight off
infection this leads to more frequent
infections increased number of
infections or increased susceptibility
to infections and these cells these
leukemia cells that are really rapidly
dividing take up a lot of the body's
energy and because of that you see
symptoms such as weakness and symptoms
such as weight loss significant weight
loss which are things that you've seen
in lots of other cancers because you
also have rapidly dividing cells and
other cancers and then finally the
leukemia cells start to grow into the
wall of the bone and if you've ever
broken if you've ever had a bone
fracture or bone infection you know that
the wall of the bone has lots of very
sensitive sensory nerves in it and
because of that the patients with
leukemia start experiencing bone pain
and that's not pain in just one bone
it's pain throughout the bones of the
body so it's more generalized bone pain
so if a patient starts showing signs and
symptoms of
a doctor will often start off by getting
a blood test if they get a blood test
the first thing that you'll see is is
this picture over here you'll see fewer
of the healthy normal cells and you may
even see the leukemia cells in the blood
right so that would lead to the
suspicion that maybe the patient has
leukemia and that suspicion can be
confirmed by looking inside by actually
looking inside the bone marrow and so
that's this I'm just drawing in the
cavity inside the bone and you can look
inside the bone marrow by actually
sticking a needle a long needle inside
the bone and drawing out some fluid and
then looking at that stuff under the
microscope and and that's actually
called a bone marrow bone marrow
aspiration so in a nutshell this is what
leukemia is all about