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Study Supports Removal of Fewer Lymph Nodes in Breast Cancer Patients (dateline October 20, 2003)


Results of a small study support the use of a less invasive type of surgery to remove lymph nodes in women with breast cancer. The procedure, called sentinel lymph node biopsy, involves removing only one to three lymph nodes in the armpit region to check whether cancer has begun to spread past the breast. The standard procedure, axillary lymph node dissection, involves removing far more lymph nodes and is sometimes associated with more severe side effects. Though results from larger studies are still needed to determine the true safety and effectiveness of sentinel lymph node biopsy, small studies continue to show that it may be a viable option for breast cancer patients.

Sentinel lymph node biopsy is a new diagnostic procedure used to determine whether breast cancer has spread (metastasized) to axillary lymph nodes (i.e., lymph glands under the arm). A sentinel lymph node biopsy requires the removal of only one to three lymph nodes for close review by a pathologist. If the sentinel nodes do not contain tumor (cancer) cells, this may eliminate the need to remove additional lymph nodes in the axillary area.

Because sentinel lymph node biopsy involves removal of fewer lymph nodes than a standard axillary lymph node dissection, the potential for side effects such as lymphedema (chronic arm swelling) is much lower. However, side effects are still possible with sentinel node biopsy, including post-operative pain, nerve damage, and arm swelling after the procedure.

While sentinel lymph node biopsy has been performed by some surgeons for years, experts cautioned that more clinical trial results were needed before the procedure became a widespread replacement for standard axillary lymph node dissection. In the current study, Umberto Veronesi, MD and his colleagues from European Oncology Institute in Milan, Italy randomly assigned 516 women with breast cancer to undergo either sentinel lymph node biopsy or traditional axillary lymph node dissection. All of the women had breast cancers that measured two centimeters in diameter or smaller. Those women whose sentinel lymph node biopsy results showed cancer then underwent full axillary lymph node dissection.

Results showed that sentinel lymph node biopsy missed cancerous cells in only 9% of cases, and in most of these instances, the women did not develop a new cancerous tumor. Women who underwent sentinel lymph node biopsy also experienced less arm pain and better mobility compared to women who underwent standard axillary lymph node dissection.

Therefore, Dr. Veronesi and his team conclude that sentinel lymph node biopsy may be an appropriate option for women with small breast cancers. However, in an accompanying editorial also published in The New England Journal of Medicine, David Krag, MD, and Takamaru Ashikaga, PhD argue that a large sample of women must be studied to determine whether sentinel lymph node biopsy truly increases the chances of surviving breast cancer.

Because the procedure requires experience to accurately identify the sentinel lymph node, the American College of Surgeons Oncology Group recommends that physicians perform at least 30 sentinel lymph node biopsies followed by complete axillary lymph node dissection, with an 85% success rate in identifying the sentinel lymph node(s) and a 5% or lower false positive rate, before performing the procedure without a back-up axillary node dissection.

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