hi guys dr. Steen here I am a surgical oncologist in California I graduated
from the University of Colorado School of Medicine and did general surgery
training at Baylor University Medical Center and I did a surgical oncology
fellowship at the John Wayne Cancer Institute the John Wayne Cancer
Institute is very famous as developing the sentinel lymph node biopsy for
melanoma today we are talking about the sentinel lymph node biopsy for melanoma
a topic I hold dear to my heart I hope this video helps you
thanks for joining me today we will be talking about the sentinel lymph node
biopsy for melanoma skin cancer melanoma is a dangerous form of skin cancer and
we want to know if it has spread to lymph nodes as this is usually the first
place it can spread in the body the sentinel lymph node biopsy is a way for
us to check the lymph nodes for cancer cells only certain lymph nodes are
connected to the area of the skin that is growing the melanoma cancer so these
are the lymph nodes we want to find and these are what are called sentinel lymph
nodes the technique is as follows a day prior to surgery or several hours before
surgery we inject a radioactive dye into the skin around the melanoma that dye
travels through the lymphatic channels and gets trapped in the first lymph node
it encounters the radioactive dye remains stuck in the lymph node until we
do surgery the radiologist can take a picture with a special camera that can
detect the radioactive signal and they will mark the area of the body that
contains the lymph node with the radioactive dye we can use a Geiger
counter in the operating room that actually allows us to detect the
radioactive material during the surgery we also inject a blue dye into the skin
that travels to the same lymph node as the radioactive dye and allows us to
identify the sentinel lymph node visually as it is stained blue for
example there are about 20 lymph nodes in the armpit we only want to remove the
one lymph node that is connected to the area of the skin with the melanoma and
that will be the lymph node marked with the radioactive and blue dye this is the
sentinel lymph node once a sentinel lymph node is identified the entire
lymph node is removed sometimes we've removed several lymph nodes if they are
all marked with the dye a lymph node is about the size of a jellybean after it
is removed a pathology doctor then cuts the lymph node into thin slices and can
tell us if there is any spread of melanoma to the sentinel lymph node this
is a very accurate way of finding even a very small area of melanoma within the
lymph node the pathologist uses not only regular stains to see the melanoma
cancer cells under the microscope but they also use special melanoma specific
stains called immunostains which can allow them to see even just a few
melanoma cells hiding within the lymph node melanoma of the hand or the arm
will almost always drain to lymph nodes in the armpit melanoma of the foot or
the leg will almost always drain to lymph nodes in the groin when we remove
the lymph node in the groin there is a one inch cut over the lymph node if it
is a left leg melanoma then the left groin will contain the sentinel lymph
node where it gets tricky is on the torso if you have a melanoma on your
chest or abdomen or back these can drain into multiple areas say you have a
melanoma on your right chest it can drain to a sentinel lymph node in the
right armpit or to one in the right groin or it could even drain all the way
over to the opposite side say to the opposite groin so the pictures that the
radiologist takes called lymphoscitigraphy are very important because they
can tell us which of these locations the melanoma has draining to and where to
remove the sentinel lymph node the upper back can actually drain up into lymph
nodes above the collarbone or even into the lower neck so there is a lot of
variable drainage in lymph nodes in the torso area the other area that can be
tricky is melanoma of the head and the neck area if you have a melanoma on the
scalp or the face these melanomas can drain cancer cells to lymph nodes in the
salivary gland in the cheek called the parotid gland or to very small lymph
nodes in the neck so that is a brief overview of the sentinel lymph node
technique for melanoma skin cancer I hope that helped don't forget to
subscribe below and check out some of my other videos such as how we remove the
actual melanoma from the skin with surgery take care