Sentinel Node Biopsy More Accurate
Sentinel node biopsy is a two-part process.
First, a nuclear medicine specialist injects the breast with tiny dose of radioactive dye in or near the cancerous tissue and around the nipple.
In a few hours, the dye travels down the lymph system to the nearest, or sentinel, nodes. Pictures will are taken, showing the pathways the dye has traveled.
In the operating room, Dr. Henry Lyle, a surgeon with Columbia-St. Mary’s Hospital, will inject a blue dye then make an incision in the armpit to the armpit lymph tissue.
"We physically look for the nodes that are blue. If they are both blue and radioactive, it is a sign that they are truly sentinel nodes," Dr. Henry explains. These are the nodes a surgeon will remove for further study than the traditional one used in a standard biopsy.
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At Columbia we have done over 200 of these cases. In our hands the accuracy is ninety-seven percent.
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Following an armpit biopsy in which all the nodes are taken, about 18 of these are selected to be cut in half and stained, and slides prepared for pathologists to examine.
"With sentinel node biopsy we remove the one or two known sentinel nodes, slice them like a loaf of bread and literally look at each slice. We stain it with two types of stains, rather than just one," Dr. Henry said.
Because the sentinel nodes have been identified and meticulously examined, Dr. Henry said that sentinel node biopsy can actually be more accurate, "with a confidence level as high as 97% that the other nodes are cancer -free," Dr. Henry said.
With sentinel node biopsy, unless a woman is also having a mastectomy or lumpectomy at the same time, she can go home the same day, return to normal activities in a few days and expect her incision to be well healed in a few weeks. If the biopsy is negative, she and her physician can determine the best course of action for treatment of the cancer in the breast.
If the biopsy comes back positive, then an armpit lymph node dissection may follow. However, there is currently an experimental study underway to determine if chemotherapy without the invasive removal of all the nodes can become the standard of the future.
"In the old days every woman with breast cancer had a mastectomy and her nodes removed at the same time. Now, I would say in our practice maybe eighty-five to ninety percent of women elect breast conservation. They get the lump removed, the lymph and armpit sampled in some way and have radiation therapy to the remaining breast," Dr. Henry concluded. "At Columbia we have done over 200 of these cases. In our hands the accuracy is ninety-seven percent."
