so welcome to another MedCram lecture we're going to talk about lung cancer
today specifically when we talk about lung cancer it's important to understand
what that means just because there's a cancer inside of
the lung it doesn't necessarily more talking about lung cancer so if you look
at the anatomy of the lung you'll see the trachea branches into the right
upper lobe the middle lobe and then the lower lobe then you've got the left
bronchus and that divides into the upper and lower and they spread out so
generally speaking these bronchi they keep dividing etc it's these areas that
give rise to the cells that cause lung cancer and that's what we call it
generally speaking we call it bronchogenic lung cancer so the lung
cancer we're talking about today is tumors that arise from the bronchus okay
there's a couple of other cancers in this general area that we're not going
to be talking about so there's a covering of the lungs called the
mesothelium and that can cause a cancer and that's called a mezzo fili oma and
that's almost always associated with asbestos exposure we're not going to be
talking about that today the other thing also that you may see is something
called a carcinoid which can be in the bronchus very vascular carcinoid that's
another tumor that arises in the lungs that we're not going to talk about today
so we're not to talk about mesothelioma we're not going to talk about Carson
we're going to talk about lung cancer another name for that is bronco genic
carcinoma and we'll talk a little bit about how that's divided so bronchogenic
carcinoma is what we're going to talk about today okay well let's talk about
some statistics that you should know in terms of epidemiology
2015 in the United States there was about 220,000 new cases in terms of
deaths in 2000 so this was in 2015 in 2012 because we have data going back to
that in terms of men and women in terms of man there were about 87,000 deaths
and in women there was about 71 thousand deaths from
lung cancer now in terms of what direction this is going in for men this
is kind of stabilized okay for women however this is still going up and
that's the concern about what's going on if I were to graph this in terms of
cancer deaths by site let's say that this was lung cancer lung if I were to
add up the other types of cancer okay this would be colon cancer this would be
breast cancer and here would be prostate cancer and in terms of actual numbers
this would be around 120,000 and this would be about 160,000 so just to give
you an idea about how many people are dying every year from lung cancer as
opposed to prostate breast or colorectal should give you the importance of this
topic it is the most common cause of cancer death in the United States and
the world you know if you want to talk about the world in 2012
so this is worldwide and there's a lot of smoking that goes on worldwide it's
quite sobering there were 1.8 million new cases and how many died that year in
2012 1.6 million in terms of lung cancer incidents looking back from 1975 to 2011
there's an interesting correlation that's occurred between the genders back
in 1975 there was many more men that were smoking than women and that went up
and peaked around 1985 or so and since that time it's been coming down at that
rate and so the peak for that was well back in terms of men back in 1985 in
terms of women however that seems to not have plateaued as as early that plateau
period seems to have been just before 2000 and it seems to be coming down just
very very slowly so the interesting thing here is is that men are still
above women in terms of incidents but they seem to be coming down at a faster
rate than the lung cancer incidents in women and we think that that's just a
little bit of a lag time there you know in terms of causes now the number one
cause of lung cancer is still active smoking and they figure that's about 90%
so what's the other 10% well it's possible that this may actually add up
to more than a hundred percent because there's usually multiple things that's
doing it but believe it or not radon which is a gas that's found in the soil
and cause about 9 to 15 percent of lung cancer
number three is Occupational and number four is environmental
so basically air pollution occupational accounts for about 10% environmental
about one to two percent let's talk a little bit about the pathophysiology of
this so if you've got the bronchus coming here typically what's going to
happen is you're going to get some sort of irritant coming down into the lungs
and these air Tain's consent them go into the cells and cause problems and as
these cells are dividing something can happen where the breaks on the cellular
division are removed and the cellular division just continues to divide and
divide and so you start to get a tumor and the tumor grows and you have
doubling times and usually it's very small you cannot pick it up on an x-ray
maybe you can pick it up on a CT scan if it's big enough but this is generally
where the tumor size is going to enlarge until it's finally picked up and this is
the reason why we call it bronco genic carcinoma now interesting we'll talk
about this later there are types of lung cancer that are
specifically associated with smoking and the two that you should know and we'll
review this later is squamous cell and small cell and it's very interesting to
note that when you look at the anatomy of the lungs that squamous and small
cell lung cancer generally are centrally located and one can think and say that
this may be related to the the smoke when it comes down it's going
to have its strongest effect effect centrally as opposed to peripherally
there are some cancers which are more common peripherally and those are not
associated with smoking but small-cell is one of them and squamous cell is the
other okay well join us for our next lecture we're going to talk a little bit
about screening and staging thank you so much
you