PIONEERING SENTINEL NODE BIOPSY IN PATIENTS WITH BREAST CANCER: New Clinical Trial of Minimally-Invasive Breast Surgery Seeks Volunteers in First Program of Its Kind on Long Island
Breast cancer is clearly the most common malignancy facing American women today, accounting nationally for an estimated 215,000 new cases in 1997. Despite an increasing incidence, mortality rates have remained the same. More women with breast cancer, in other words, are surviving in the face of the growing number of cases—most likely as a result of earlier detection, treatment improvements, and an overall increase in breast cancer awareness.
The hopeful news is that advances in the surgical treatment of this disease are being made by physicians—with the vital help of patients themselves.
From Radical to Conservative Therapy
Radical mastectomy used to be the only treatment for breast cancer. This operation, which involves removing the entire breast, lymph nodes, and chest muscles (pectoralis major and minor), remained the gold standard for treating breast cancer for the better half of this century. However, two carefully done clinical trials performed in the 1970's showed that modified radical mastectomy was equivalent to radical mastectomy in most patients with breast cancer.
This modified radical mastectomy preserved the pectoral muscles, resulting in less deformity. Modified radical mastectomy then became the procedure of choice for most patients with breast cancer.
More recently, breast conservation therapy has been used as an alternative to mastectomy in selected patients with breast cancer. When conservation is used, the tumor itself is removed with a surrounding rim of healthy breast tissue. The remainder of the breast remains intact. This procedure is called lumpectomy. Radiation therapy is then used to reduce recurrence in the breast. As early as 1961, clinical trials were investigating the feasibility of breast conservation as an alternative to mastectomy.
Over the ensuing twenty years, thousands of women with breast cancer voluntarily enrolled in clinical trails designed to evaluate the safety of breast conservation. The voluntary participation by these women enabled these clinical trials to prove that lumpectomy plus radiation therapy is a safe alternative to mastectomy in most patients with small cancers. This finding was of enormous importance, in that it ushered in a new era of conservatism in the surgical treatment of breast cancer.
Now, mastectomy can be avoided in many patients with breast cancer.
Advancing Treatment of the Axillary Nodes
As the issue of the safety of breast conservation was laid to rest, breast cancer researchers shifted their focus to the treatment of the axillary (underarm) lymph nodes. These nodes, which are part of the lymphatic system that removes wastes from body tissue, may be the first place affected when breast cancer begins to spread.
Axillary nodes are routinely removed during breast cancer surgery in order to determine whether or not the cancer has spread to them. Additionally, removing the lymph nodes greatly reduces the chance of tumor recurrence in the underarm area. However, today as many as 70% of patients with breast cancer have nodes that are free of tumor. Clearly, in these patients, removal of the axillary nodes provides no benefit at all. In fact, removal of the axillary nodes is occasionally associated with some scarring, numbness, and swelling of the arm.
This dilemma has led researchers to develop a less invasive procedure that would accurately determine whether or not the axillary nodes are affected by cancer, without having to remove them all. The newly developed procedure is called sentinel node biopsy. It enables the surgeon to identify and remove the first draining lymph node—the "sentinel" node—in the underarm area. The status of this representative node is then used to assess the health of the remaining nodes.
Preliminary results from studies in Vermont and California are encouraging, and strongly suggest that sentinel node biopsy is an accurate predictor of whether or not the cancer has spread to these remaining nodes.
Early this year, breast cancer physicians at Stony Brook's University Hospital and Medical Center began a clinical trial to confirm that sentinel node biopsy is a safe and accurate alternative to full removal of the axillary nodes. Eligible patients with breast cancer have a sentinel node biopsy. In the current preliminary phase of this study, all patients also have the remaining axillary nodes removed and analyzed, so that the accuracy of the sentinel node procedure can be validated.
In the Operating Room
In sentinel node biopsy, a small amount of radioactive dye is injected into the breast around the site of the cancer. This test helps to determine the location of the lymph nodes that are draining the breast cancer. The amount of radioactivity is very small, less than that used for a chest x-ray or a bone scan, and generally does not cause any problems.
In the operating room, a small amount of blue dye is injected around the tumor as well. Both the blue dye and the radioactive dye travel towards the patient's underarm via lymph vessels, helping the surgeon to find that first draining lymph node.
Next, the surgeon uses a geiger counter-like device (probe) to locate and count the small amount of radioactivity injected earlier, which is now trapped in the first draining axillary lymph node (sentinel node). An incision is then made in that location, and the sentinel node, identified by both the gamma probe and the blue dye, is removed.
Brian J. O'Hea, MD, assistant professor of surgery and medical director of Stony Brook's Carol M. Baldwin Breast Care Center, says, "We believe that sentinel node biopsy will indeed prove to be a safe and accurate alternative to full axillary surgery in patients with breast cancer, and thus will constitute an important new advance in breast cancer surgery."
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In recent years, tremendous strides have been made in the surgical treatment of breast cancer. These strides have brought us from an era of radical surgery towards more conservative procedures such as lumpectomy. Breast cancer physicians as well as the entire medical community are to be commended for this progress.
But the real heroes in the quest for a cure are the breast cancer patients themselves, who have voluntarily enrolled themselves in scientifically directed clinical trials.
These carefully designed clinical trials have answered some very important questions about the treatment of breast cancer. Although the patients in these studies may not derive any direct benefit themselves, their participation in these trials has clearly benefitted many women who are subsequently diagnosed with breast cancer.
For more information about Stony Brook's clinical trial of sentinel node biopsy, please call the Carol M. Baldwin Breast Care Center at 631-444-4550 for an appointment with one of the breast surgeons.
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