Dr. White Discusses the Z11 Trial Radiation Findings

Julia R. White, MD, Professor of Radiation Oncology, Medical College of Wisconsin, Medical Director, Radiation Oncology, Community Memorial Hospital, discusses the radiation findings from the Z11 randomized trial looking at sentinel node positive patients that received either axillary node dissection or observation.

The trial found axillary node recurrence did not change based on dissection. The survival and recurrence rates were similar in both arms. The trial suggests that sentinel node biopsy is sufficient alone in patients with T1, HR-positive, with no lymphovascular invasion, that will be receiving breast irradiation.

It is possible that the standard breast irradiation accounts for the low levels of recurrence. In the process of standard radiation a corner of the axilla does receive radiation that reaches 25-50% of levels 1 and 2 in the axilla. This portion of the axilla is generally the area removed during dissection.

For patients meeting the Z11 criteria it is possible to provide sufficient axillary control with breast irradiation alone without the need for dissection. The radiation oncologist should not change their practice based on the Z11 results.