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 (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 usually is recommended only for certain women diagnosed with breast cancer that has already 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.
Research suggests that including the internal mammary lymph nodes in the radiation treatment area for women diagnosed with early-stage breast cancer that is large and/or has spread to one or more lymph nodes doesn't reduce the risk of the cancer coming back in the same area or improve survival. The results were presented at the September 2011 Multidisciplinary Breast Cancer Symposium.
When deciding on breast cancer treatments, you and your doctor will carefully weigh the benefits against any risks. Expanding the radiation treatment area to include the internal mammary lymph nodes generally should be done only if it reduces the risk of the cancer coming back and/or improves overall survival.
In this Canadian study, researchers looked at the records of more than 2,400 women diagnosed with early-stage breast cancer that was large in size and/or had spread to one or more lymph nodes under the arm (axillary lymph nodes). The radiation therapy plan for 1,000 of the women included the internal mammary lymph nodes in the radiation treatment area. The women were followed for a little more than 6 years.
The risk of the cancer coming back in the same area and overall survival were the same for women who received internal mammary node radiation and women who didn't.
The results suggest that internal mammary node radiation doesn't improve treatment outcomes. Other older 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 radiation shouldn't be used unless it offers some benefit.
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 node radiation makes sense for your unique situation.
Although this study suggests that internal mammary node radiation shouldn't be done routinely, it still may make sense for you based on the specifics of your situation. This may be especially true if your risk of the cancer coming back in the same area is much higher than average.
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.