Sentinel Lymph Node Biopsy

WHAT IS A SENTINEL LYMPH NODE?

• Lymph nodes are small, gland-like structures that occur in clusters in several areas of the body. They act as filters to trap bacteria (germs) and possibly cancer cells that may travel to lymph tissue that is close to the tumor.
• In the breast, a group of lymph vessels drains fluid and cells to a chain of lymph nodes in the axilla (armpit). In theory, the ‘sentinel’ node is the very first lymph node in the chain to receive drainage from an area of the breast that contains cancer cells.
• If the sentinel node does not contain breast cancer cells, the cancer has not spread beyond the breast.

WHAT IS A SENTINEL LYMPH NODE BIOPSY?

• When breast cancer is diagnosed, an axillary lymph node dissection (AND) is done to check for the metastasis (spread) of cancer. Ten to 20 lymph nodes are usually removed.  This procedure is done to determine the extent of the cancer or to ‘stage’ the cancer (see staging information on this website).
• Sentinel lymph node biopsy (SLNB) requires the removal of only one to three lymph nodes. 
• At this time, surgeons perform the sentinel lymph node biopsy with or without an axillary node dissection for staging.  Increasing evidence supports the use of Sentinel lymph node biopsy in early stage breast cancer.

THE PROCEDURE

• This is a two-part procedure which involves the sentinel lymph node mapping and the surgical removal of the sentinel node.

SENTINEL LYMPH NODE MAPPING

• The sentinel lymph node mapping is done the day before surgery or the morning of surgery, in the Nuclear Medicine Department.
• You will be given an injection of a small amount of radioactive material near the areola (dark skin around the nipple) in the quadrant of the breast where the breast cancer is located.
• EMLA cream can be used to numb the skin to make the injections more comfortable (see instructions below).
• There is a two-hour wait to allow the radioactive material to be absorbed by the lymph vessels.  You do not need to stay in the department during this time.
• You will be placed under a scanner and three different images of your chest and armpit will be taken.
• The radiologist uses the images to find the sentinel node. The skin will then be marked with ink.  Occasionally, more than one sentinel node is found. 
• Sometimes a sentinel node is not found and you may need a standard axillary node dissection. Your surgeon will discuss this with you.
• If your surgery is the next day, there are no special instructions for the evening.  Be sure to follow the surgery preparation instructions that were given to you.  The ink mark on your skin will not wash off with bathing.

SURGICAL REMOVAL

• The removal of the sentinel node is done in the operating room by your surgeon.
• A blue dye tracer is often used to aid in identifying the node.
• The sentinel lymph nodes are sent to a lab to be closely examined by a pathologist. 

APPLYING EMLA CREAM

You should not use EMLA cream if you have had an allergic reaction to local anaesthetic in the past.

Buy a 5 gram tube of EMLA (costs about $12.00) at a drugstore.  You do not need a prescription, but you must ask the pharmacist for it because it is kept behind the counter.  Two hours before you are scheduled for the injections, apply a thick layer of EMLA cream (like icing on a cake) in a 7.5 cm (3 inch) wide oval covering the skin of the areola and a small area of the breast where the tumour is located.  For example, for a tumour at the 9 o'clock position in the right breast, you would apply the EMLA cream in this way.

 

Apply the cream directly from the tube.  Do not touch the cream with your fingers or rub in the cream.  It is important not to get the cream in your eyes.  Cover the cream with the dressing your nurse has supplied or with plastic kitchen wrap (for example, Saran®).  Follow these same instructions if you need to have a needle localization (wire insertion into the breast) before your sentinel node injections.  Bring the rest of the EMLA cream with you as the cream may need to be wiped off during the needle localization procedure and then reapplied. 

 

Appointment for Sentinel Lymph Node Mapping

 

Date: __________________________________

Time:  __________________________________

• Peter Lougheed Centre (PLC) - Main Floor, Diagnostic Imaging Department.  If booked the day before or day of surgery, report to the Admitting Department 15 minutes before your appointment.
• Foothills Medical Centre (FMC) - Ground Floor, Special Services Building.  If booked the day before surgery, go directly to the Nuclear Medicine Department 15 minutes before your scheduled time.  If booked the day of surgery, report to the Admitting Department as directed.
• Rockyview General Hospital (RGH) - Report directly to the Main Floor, Diagnostic Imaging Department.