Lymph Node Radiation Better for Some Breast Cancer Patients

A phase 3 study shows radiation to the regional lymph nodes in some women with early-stage breast cancer that was either node-positive or high-risk, node-negative could reduce the risk of recurrence and increase disease-free survival.

Researchers are calling it “potentially practice-changing” although emphasizing that the decision to radiate additional tissue around the tumor site is an individual choice and is not without its risks.

Women with large tumors (larger than 5 cm) or cancers with more than three positive lymph nodes typically receive whole breast radiation plus radiation to the surrounding nodes. However, ongoing controversy exists on the need for additional radiation for women with smaller tumors or one to three positive lymph nodes.

Timothy J. Whelan, with the NCIC Clinical Trials Group in Canada, led the phase 3 study that attempted to determine if nodal radiation in addition to whole-breast radiation after lumpectomy benefited this subset of patients. Interim data after a median five-year follow up did show that women with lymph node-positive or high-risk, lymph node-negative disease have about one third fewer metastatic recurrences than women who received radiation to the tumor site only (reducing the rate from 13 percent to 7.6 percent). Relative risk of local recurrence was also reduced (5.5 percent to 3.2 percent).

Although data hint at an improved survival benefit as well, the results are not statistically significant at the time of this early analysis, meaning researchers cannot rule out that the 24 percent decrease in mortality was by chance.

Increased risk of pneumonitis, which is inflammation of the lung and lymphedema was seen with the nodal radiation.