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Radiation to Specific Lymph Nodes Linked to Improved Survival in Early Breast Cancer

Among patients with early breast cancer, radiation delivered to the lymph nodes located behind the breast bone and above the collar bone is associated with improved survival. These results were recently presented at the 2013 European Cancer Congress (ECCO 2013).

The optimal role of radiation continues to be explored among women with early breast cancer, as healthcare providers strive to maximize treatment potential by providing the greatest chances for long-term survival without over-treating patients (which can result in unnecessary side effects).

Typically, women with early breast cancer have radiation given to the lymph nodes under their arms, as this is a common place to which cancer spreads. However, the side effects balanced with survival outcomes is still being evaluated in terms of radiation to the internal mammary (IM) lymph nodes, which are the nodes behind the breast bone, and radiation to the medial supraclavicular (MS) nodes, which are the nodes just above the collarbone.

To further explore the outcomes associated with radiation to the IM and MS nodes, researchers affiliated with the EORTC Radiation Oncology and Breast Cancer Groups conducted an international clinical trial including 4,004 patients from 43 medical centers. Participants had stages I-III breast cancer, the majority of whom underwent breast-sparing surgery. Some patients received IM/MS radiation while others did not. Average follow-up was approximately 11 years.

Overall survival was significantly improved among women who received radiation to the IM/MS nodes (82.3%) compared to those who did not receive radiation to IM/MS nodes (80.7%).
There were no differences in non-cancer mortality rates between the two groups, indicating the additional radiation therapy did not increase death rates from side effects.
Disease-free survival was also significantly improved among women who received radiation to the IM/MS nodes (72.1%) compared to those who did not receive radiation to IM/MS nodes (69.1%)
The researchers concluded that radiation to the IM and MS lymph nodes improves overall and disease-free survival among women with early breast cancer. However, in order for this treatment strategy to become standard therapy, future trials are necessary to confirm these findings. Radiation oncologists are still exploring whether the site of cancer, as well as size, stage and spread to nodes make a difference in whether radiation to the IM/MS nodes affect outcomes.

Reference: Poortmans P, et al. Irradiation of the internal mammary andmedial 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 22922/10925. Abstract BA 2. Presentation of the presidential session at the 2013 European Cancer Congress (ECCO). Available at: http://eccamsterdam2013.ecco-org.eu/Global/News/ECC-2013-Press-Releases-EN/2013/09/Treating-chest-lymph-nodes-in-patients-with-early-breast-cancer.aspx.