Oncologist-approved cancer information from the American Society of Clinical Oncology
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Radiation Therapy to Lymph Nodes Decreases Recurrences in Women With Early-Stage Breast Cancer

ASCO Annual Meeting
June 4, 2011

In a recent study, researchers found that radiation therapy to the regional lymph nodes decreases recurrences (cancers that come back after treatment) for women with early-stage breast cancer that has spread or is likely to spread to the lymph nodes. Regional lymph nodes are the lymph nodes near where the tumor started. For breast cancer, these are the lymph nodes in the armpit on the same side of the body where the cancer began, called the axillary lymph nodes.

Breast cancer that has spread to the regional lymph nodes is called node-positive breast cancer. It is usually treated with surgery to remove the tumor (called breast-conserving surgery) and an axillary lymph node dissection, which is surgery to remove the axillary lymph nodes. Then, radiation therapy is given to the entire breast. If the tumor is larger than 5 cm or there are more than three positive axillary nodes, radiation therapy to the lymph nodes is given. This study was designed to look for a benefit to adding radiation therapy to treatment for women who would not normally have radiation therapy to the regional lymph nodes.

The study included 1,832 women with node-positive breast cancer or high-risk, node-negative breast cancer who had breast-conserving surgery and chemotherapy or hormone therapy and then received either radiation therapy to the breast only or radiation therapy to the breast and the regional lymph nodes.

After around 5 years, about 3% of the women who also received radiation therapy to the regional lymph nodes had a recurrence near where the tumor started and about 8% had the cancer return in other parts of the body, compared with almost 6% and 13% of women who received radiation therapy to the breast only. Women who received radiation therapy to the breast and the regional lymph nodes were also more likely to live longer; however, this result was not statistically significant, which means that it could be due to chance and not the treatment.

The side effects of radiation therapy to both the breast and the regional lymph nodes included pneumonitis (swelling of the lungs) and lymphedema (abnormal buildup of fluid in the arm, causing swelling). 

What this means for patients

“These results will encourage doctors to offer all women with node-positive disease the option of receiving radiation therapy to the regional lymph nodes,” said Timothy J. Whelan, BM, BCh, lead study investigator for the National Cancer Institute of Canada Clinical Trials Group and Professor of Oncology and Division Head of Radiation Oncology at McMaster University in Ontario, Canada. “This treatment improved disease-free survival, lowered the risk of recurrences, and there was a positive trend toward overall survival, while not greatly increasing side effects.”

Questions to ask your doctor

  • What type of breast cancer do I have?
  • Has it spread to the lymph nodes?
  • What is my risk of recurrence?
  • What are my treatment options?
  • Do you recommend radiation therapy?

For More Information

Guide to Breast Cancer

Understanding Radiation Therapy

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