After surgery to remove early-stage breast cancer, many women will have radiation therapy to the breast area. Radiation is given to reduce the risk of the cancer coming back in the breast area and nearby tissue (doctors call this loco-regional recurrence).
Doctors sometimes also recommend that lymph nodes near the area where the breast cancer was removed be included in the area that gets radiation. This is called regional lymph node radiation. Regional lymph node radiation may include the internal mammary lymph nodes, which are the nodes underneath the chest wall. Regional lymph node radiation also may include the supraclavicular lymph nodes, which are just above the collar bone, near the hollow of the neck.
Regional lymph node radiation usually is recommended only for certain women diagnosed with breast cancer that already has spread to one or more nearby lymph nodes and who are considered to have a higher-than-average risk of the breast cancer coming back in the same area.
A European study suggests that women diagnosed with early-stage breast cancer that had spread to the lymph nodes had better overall survival when they received radiation to the internal mammary and supraclavicular lymph nodes after breast cancer surgery compared to women who didn’t get radiation to that area.
Overall survival is how long the women lived, with or without the cancer growing.
The research, “Irradiation of the internal mammary and medial supraclavicular lymph nodes in stage I to III breast cancer: 10 year results of the EORTC Radiation Oncology and Breast Cancer Groups phase III trial,” was presented at the European Cancer Congress on Sept. 29, 2013.
About 4,000 women diagnosed with early-stage breast cancer that had spread to the axillary lymph nodes (the lymph nodes in the armpit) from 43 cancer centers in Europe participated in the study:
- about 75% of the women had lumpectomy plus radiation; 85% of these women had a radiation boost, a supplement dose of radiation targeted directly to the area where the cancer was
- 73% of women who had a mastectomy were treated with radiation therapy to the chest wall
After these treatments, the women were randomly assigned to receive either:
- radiation therapy to the internal mammary and supraclavicular lymph nodes
- no radiation therapy to those lymph nodes
After about 10 years of follow-up, the researchers found that women who received radiation therapy to the internal mammary and supraclavicular lymph nodes had better overall survival than women who didn’t get radiation to those lymph nodes, no matter how many lymph nodes had breast cancer in them:
- 82.3% of the women who had internal mammary and supraclavicular lymph node radiation were alive
- 80.7% of women who didn’t get radiation to those lymph nodes were alive
The researchers also reported that radiation to the mammary and supraclavicular lymph nodes didn’t cause any additional side effects beyond what is expected with standard radiation therapy.
Other earlier research suggests that internal mammary node radiation may possibly increase the risk of uncommon heart and lung problems because these healthy tissues are unintentionally exposed to radiation. Advances in radiation therapy technology in recent years make it much less likely that healthy nearby tissue such as the heart and lungs will be unintentionally exposed to radiation. Still, internal mammary node and/or supraclavicular node radiation shouldn't be used unless it offers some benefit.
Other research suggests that internal mammary node radiation doesn’t reduce the risk of recurrence.
When deciding on breast cancer treatments, you and your doctor will carefully weigh the benefits of each treatment against any risks. Expanding the radiation treatment area to include the internal mammary and supraclavicular lymph nodes generally should be done only if it reduces the risk of the cancer coming back and/or improves overall survival.
If you've been diagnosed with early-stage breast cancer, it's a good idea to ask your doctor if the cancer has spread to the lymph nodes and the treatment options recommended because of that spread. You may want to ask about your risk of the cancer coming back and if radiation therapy is recommended for you, as well as whether internal mammary and/or supraclavicular node radiation makes sense for your unique situation.
Visit the Breastcancer.org Radiation Therapy section to learn more about the role of radiation therapy in breast cancer treatment, the ways it may be given, and what to expect during treatment.