Keep those lymph nodes, ladies.

Ever since her breast cancer surgery our friend Gwen has had some swelling of her right arm. That is the side where the cancer was found and where her surgeon removed the lymph nodes from under that arm. This swelling of the arm, called lymphedema, happens often when those lymph nodes are taken. The lymphatic system, which gets disrupted in this surgery, plays an important role in channeling fluid from our arms as well as other parts of the body.

Now a new study finds that Gwen cold have done without this surgery. To understand why lymph nodes are taken, we have to understand the history of breast cancer surgery. Around the beginning of the 20th century, breast cancer surgery was developed by William Halstead, a surgeon from Johns Hopkins. At that time, women were seeking treatment only when the cancer had gotten fairly large. In order to prevent the cancer from coming back on the chest wall, Halstead developed a procedure called the radical mastectomy. This involved taking of the breast, the lymph nodes under the arm, which were generally filled with cancer, and the chest muscle under the breast.

With time, modern medicine discovered that this kind of an operation was no longer needed for today’s women who generally present with small tumors, often discovered by mammography. Today, such a woman would receive a lumpectomy and a sentinel node biopsy, that is, removing just a few lymph nodes from under the arm, which have been identified as the lymph nodes where the cancer would most likely spread. The main purpose of this procedure would be to determine the stage of the cancer. If there has been spread, chemotherapy and hormone therapy would be considered after the surgery.

Still, if these lymph nodes contain cancer, as did Gwen’s, surgeons like Gwen’s would take out more, usually an additional 15 to 25 lymph nodes. This is based more on tradition than science; it was assumed that if we left some cancer behind in lymph nodes, the cancer would be more likely to come back.

Now we know this isn’t true. A large group of breast cancer surgeons from around the U.S. asked whether they really had to remove all the lymph nodes if just those few sentinel nodes contained cancer. They studied around 900 women whose sentinel lymph nodes contained cancer. In half those women, they removed the rest of the lymph nodes from under the arm; the other half had no further surgery. After 8 years there was no difference in the groups. They had the same rate of recurrence and just as many women who had the bigger operation died of breast cancer as did women who only had the sentinel node operation. This was reported in the February 9, 2011 issue of the Journal of the American Medical Association.

Why did this take so long. Tradition dies hard in medicine, especially among surgeons who were trained to do an operation in a certain way and often trained many years ago. Also it seems logical that if there is cancer left behind (about one-fourth of the women with the bigger operation had cancer in the remaining lymph nodes) the cancer would be more likely to come back. But modern treatment with chemotherapy and hormone therapy seems to be able to take care of this remaining cancer.

What about Gwen? She feels a little sad that this report came out too late for her to avoid her extra surgery and wishes she could have had a choice.