So you’ve been diagnosed with breast cancer and now you are being bombarded with surgical options and terminology. Your surgeon mentions the possibility of a sentinel node biopsy (SNB). He talks about it being a less invasive procedure but it’s all so confusing. Your initial instinct is “Just take it all! I want all the cancer gone!” Hopefully, the following article will take some of the mystery out of what your surgeon is talking about and help you with your decision. However, I am not a physician and if you have questions, please consult your doctor.

Background

First of all, we need to know what the lymph nodes are and what purpose they serve. The lymph system is like your blood vessels in that it runs throughout our bodies but it carries lymph. This lymph is a fluid that surrounds all the cells in our bodies and helps remove waste products from these cells. The excess lymph drains from areas through lymph vessels which then dump into lymph nodes. The lymph also plays a major roll in fighting off foreign cells like bacteria. That is why your lymph nodes might be swollen if you are fighting an infection. These nodes are collection points and they tend to be grouped together in certain parts of your bodies such as your underarms (axilla) or your groin. The lymph nodes actually filter the lymph fluid and capture the invading cells before it dumps the excess lymph into the bloodstream. The nodes are full of antibodies that then attack the invader.

That brings us back to our breast cancer. The lymph node sees the cancer as an invader and traps most of it there. That is why your surgeon wants to test your lymph nodes- it is the likely place to find the cancer if it has spread. If the cancer isn’t detected in the lymph node, then it tells your doctor that it is probably confined to the initial area.

Until the mid 1990’s, the standard for doctors was to do a full axillary (armpit) node dissection for women with invasive breast cancer, unless the size of the tumor required chemotherapy anyway. This means the surgeon removed a wedge of tissue from the armpit to gather a number of lymph nodes. There are three groups of lymph nodes in the underarm and the surgeon’s wedge usually tries to remove the lower two of these groups. This leaves some nodes to help with the drainage in your arm. However, all women are different and the number of nodes in that wedge varies greatly. That’s why some women say they had 10 nodes removed and others 25. The pathologists then determine how many of the lymph nodes show signs of cancer cells. The more nodes that are positive for cancer, the more likely the cancer has reached the bloodstream. Once in the bloodstream, the cancer can spread to other parts of the body. However, this is by no means a death sentence! It just tells your doctor how aggressively and with what types of chemo to treat your cancer.

Losing most of your lymph nodes in your arm pit can have numerous possible side effects including nerve damage and lymphedema. You are also susceptible to swelling (lymphedema) in that arm because you don’t have all the nodes to help rid your body of the excess lymph. In addition, you have an increased risk of infection in that arm. However, all of these possible side effects have been worth the risks in that valuable information about your cancer can be learned. The trouble is that 75% of women have no cancer in their nodes so they have had the surgery unnecessarily. Up until recently there has been no way to know which group you are in, so most women have had the full axillary excision.

In the mid-1990s, researchers developed a new procedure called a Sentinel Node Biopsy (SNB). A sentinel node is the first one or two axillary nodes that your lymph drains to from the area of your cancer. The idea is that if the cancer hasn’t made it to one of these first nodes, then it shouldn’t be in any others. Consequently, if doctors can locate these sentinel nodes, you can possibly avoid the full axillary dissection. I say possibly because if cancer is found in your sentinel node, than the doctors will want to take a wedge of tissue to harvest more nodes for staging your cancer. So the SNB is a boon to women who don’t have cancer in their lymph nodes because they can avoid many of the problems of axillary dissection.

SNB Procedure

So you’ve agreed to the SNB and now you want to know what to expect. The SNB is more complex than the full axillary excision in that it takes a team of experts working together to identify, remove, and finally test the sentinel nodes. Because the procedure is relatively new, it may not be available everywhere. In fact, because of the complexity, I was told that you should make sure that your surgeon and his team should have special training and a lot of experience with the procedure. Otherwise, they may fail to identify the sentinel node and you may have all your nodes removed unnecessarily. However, let me start at the beginning on the day of surgery.

 The first thing necessary is the sentinel node mapping which basically means they need to locate the sentinel nodes. Some doctors use a blue dye and others use a radioactive tracer. More and more doctors are using both because they each have their advantages. If a radioactive tracer is used, the surgery should occur within 2-6 hours of the injections. The blue dye is usually injected immediately before surgery.

If your doctor is using the radioactive tracer, you must have the tracer injected into the tissue adjacent to your cancer. If the cancer is very small, you might have needle localization. This is where a doctor locates your cancer with ultrasound and then inserts a needle leaving the tip of the needle at the edge of the cancer. This way the doctor knows exactly where to inject the radioactive material and where to perform the surgery. Once injected you must wait at least a half hour while the tracer has a chance to drain to your lymph nodes. I was advised to move my arm up and down to help move the fluid along. The technician said they get better results this way.

After the tracer has had a chance to drain to your lymph nodes, you are put on a table where an x-ray type machine scans your chest. Special tags are place on your chest that show up on your scan to give your doctor a frame of reference. The scanner picks up any radioactive material. You can see a big “hot spot” where the radioactive tracer was injected. Then if you are lucky, one or two other spots will show up. These are your sentinel nodes. However, if your cancer is close to the armpit, you may not be a good candidate for SNB. This is because the “hot spot” is too close to the axillary nodes and the sentinel nodes can’t be differentiated.

Now that your sentinel nodes have been mapped, you are prepped for surgery. While under anesthesia, blue dye will be injected into your tumor area minutes before surgery starts. The breast will be massaged so that the dye will work its way to the sentinel nodes quicker. This makes the sentinel node much easier to find once the incision is made. The surgeon will also use a hand held Geiger counter-like probe. With this probe, the surgeon will now know exactly where to make his incision so it can be much smaller than if he had to search for your nodes.

Between the dye and the radioactive tracer, the doctor will identify and remove one or more nodes. While the surgeon does the lumpectomy, a pathologist will look at the sentinel nodes. If he/she determines that there is cancer present, word will be sent to the surgeon who then takes the full wedge of tissue from under the arm to get more nodes. If this is done, a drain is usually inserted to help with the excess fluid for the first days after the surgery. If no cancer is found, the doctor can avoid putting in the drain and the recovery is much quicker.

After the surgery, you will experience two effects directly related to the SNB procedure. One is that the first time you urinate- your urine will be blue. In addition, for several weeks you make notice the skin of your breast has a blue tinge. This will eventually dissipate.