More Extensive Radiation Therapy May Provide Benefit in Early Breast Cancer
The addition of regional lymph node irradiation (radiation therapy to lymph nodes around the breast) may improve outcomes for some women with early breast cancer. These results were published at the 2011 annual meeting of the American Society of Clinical Oncology.
Treatment of early breast cancer often involves breast-conserving surgery, whole-breast radiation therapy, and (when appropriate) systemic therapies such as chemotherapy and hormonal therapy. When the cancer has high-risk features, such as a large tumor size or more than three positive axillary (under-the-arm) lymph nodes, treatment may also involve radiation to the lymph nodes around the breast (regional nodal irradiation). For women with only a few positive axillary lymph nodes, however, it’s been uncertain whether this more extensive radiation provides a benefit. It is estimated that about 14% of women diagnosed would have 1-3 positive nodes.
To evaluate regional nodal irradiation, researchers conducted a study among 1,832 women with node-positive or high-risk node-negative breast cancer. In addition to breast-conserving surgery and other standard breast cancer treatments, women were assigned to receive either whole-breast radiation therapy or whole-breast radiation therapy plus regional nodal irradiation.
- Regional nodal irradiation reduced the risk of cancer recurrence. At five years, the risk of developing a recurrence in or near the breast was 3.2% among women treated with whole-breast radiation therapy plus regional nodal irradiation, compared with 5.5% among women treated with whole-breast radiation therapy alone.
- Regional nodal irradiation also reduced the risk of cancer recurrence at other sites in the body. Risk at five-years was 7.6% among women treated with whole-breast radiation therapy plus regional nodal irradiation, compared with 13% among women treated with whole-breast radiation therapy alone.
- Regional nodal irradiation increased the risk of side effects such as lymphedema (swelling caused by a build-up of lymph fluid) and pneumonitis (inflammation of the lungs).
In a prepared statement, the lead author of the study noted “These results are potentially practice-changing. They will encourage physicians to offer all women with node-positive disease the option of receiving regional nodal irradiation. Adding regional nodal irradiation improved disease-free survival, lowered the risk of recurrences, and there was a positive trend toward improved overall survival, while not greatly increasing toxicities.”
Reference: Whelan TJ, Olivotto I, Ackerman I et al. NCIG-CTG MA.20: An intergroup trial of regional nodal irradiation in early breast cancer. Paper presented at: 2011 Annual Meeting of the American Society of Clinical Oncology; June 3-7, 2011; Chicago, IL. Abstract LBA1003.