Researchers found that women with breast cancer who had additional underarm lymph nodes removed after cancer was found in the sentinel lymph node did not live longer than women who had no additional lymph nodes removed. Lymph nodes are the tiny, bean-shaped organs that help fight infection. Doctors examine lymph nodes to learn whether the breast cancer has spread using a sentinel lymph node biopsy. In a sentinel lymph node biopsy, one or a few lymph nodes are removed from under the arm, which is where breast cancer is most likely to spread first. If the sentinel node is cancer-free, then it is likely that the other lymph nodes do not have cancer either. However, if the sentinel lymph node shows evidence of cancer, then doctors often examine additional lymph nodes for cancer in a process called an axillary lymph node dissection. The advantage of a sentinel lymph node biopsy is that it avoids the side effects of an axillary lymph node dissection, such as pain and discomfort and swelling of the arm.

In this study, doctors wanted to find out whether axillary lymph node dissection was necessary for women with small amounts of cancer (called micrometastases) in the sentinel node by comparing the five-year survival rates for women who had additional lymph nodes removed with those who did not. All women who participated in this study had a lumpectomy (removal of the tumor and a small cancer-free margin of tissue), radiation therapy, and a sentinel lymph node biopsy that showed cancer cells in the underarm lymph nodes.

What this means for patients

“Axillary lymph node removal has been the standard approach for women with micrometastases in the sentinel lymph node,” said lead author Armando E. Giuliano, MD, Director of the John Wayne Cancer Institute Breast Center in Santa Monica, California. “Our findings suggest that there may not be a benefit to removing more lymph nodes than only the sentinel node, and that women can avoid the risk of additional side effects that come with more extensive lymph node removal. Axillary lymph node dissection may still be needed for some women, but these findings show it may be necessary for far fewer women.”

What to Ask Your Doctor

• What are the results of the sentinel lymph node biopsy? What does this mean?
• Do you recommend an axillary lymph node dissection?
• What are the side effects of these procedures? Can they be prevented or minimized?
• What is the benefit of having more lymph nodes removed?
• What is the chance that the breast cancer will spread?
• What are my treatment options?

For More Information

Guide to Breast Cancer [1]

ASCO Answers Fact Sheet: Breast Cancer [2]

What to Know: ASCO's Guideline on Sentinel Lymph Node Biopsy for Early Breast Cancer [3]

After Treatment for Breast Cancer: Preventing Lymphedema [4]