Chemotherapy Before Surgery May Mean Lymph Node Radiation Not Needed
People diagnosed with early-stage, lymph node-positive breast cancer – meaning cancer is in the lymph nodes – who received chemotherapy before surgery and were then found to no longer have cancer in the lymph nodes (negative lymph nodes) may not have to have lymph node radiation, according to a study.
Treatments given before surgery are called neoadjuvant treatments.
The research was presented on Dec. 6, 2023, at the San Antonio Breast Cancer Symposium. Read a media release and the abstract of “Loco-Regional Irradiation in Patients with Biopsy-proven Axillary Node Involvement at Presentation Who Become Pathologically Node-negative After Neoadjuvant Chemotherapy: Primary Outcomes of NRG Oncology/NSABP B-51/RTOG 1304.”
Why do the study?
When early-stage breast cancer is found in the lymph nodes during a biopsy, chemotherapy before breast cancer surgery is often recommended. This is to destroy the cancer cells in the lymph nodes, as well as any cancer cells that may have spread to parts of the body beyond the lymph nodes.
In some cases, the chemotherapy completely gets rid of all the cancer cells in the lymph nodes. The cancer is then considered to be node-negative. Currently, there is no standard treatment for breast cancer that converts from lymph node-positive to lymph node-negative.
“There is an active debate on whether these patients should be treated as patients with lymph node-positive disease, which is how they were diagnosed, or as patients with lymph-node negative disease, which is how they present at the time of surgery,” said Terry Mamounas, MD, MPH, who presented the research. Dr. Mamounas is chair of the NRG Oncology Breast Committee, professor of surgery at the University of Central Florida, and medical director of the Comprehensive Breast Program at the Orlando Health Cancer Institute.
If breast cancer in those situations is treated as lymph node-positive, doctors would recommend that people have chest wall and lymph node radiation after mastectomy, or whole-breast and lymph node radiation after lumpectomy.
If the cancer is treated as lymph node-negative, people would be able to skip lymph node radiation after surgery. That would mean that people who had mastectomy would have no radiation and people who had lumpectomy would just have whole-breast radiation.
This study was designed to see if people diagnosed with node-positive breast cancer that converted to node-negative disease after neoadjuvant chemotherapy could safely skip lymph node radiation.
About the study
The study included 1,556 people diagnosed with early-stage, node-positive breast cancer. All the people received neoadjuvant chemotherapy and were found to have negative lymph nodes after either mastectomy or lumpectomy, plus lymph node removal. People diagnosed with HER2-positive disease also received anti-HER2 medicine along with chemotherapy before surgery.
The people joined the study between September 2013 and December 2020.
The researchers evenly split the people between two treatment groups:
one group received no lymph node radiation; the people in the group were monitored after either mastectomy or lumpectomy plus whole-breast radiation
the other group did receive lymph node radiation; the people received either chest wall radiation and lymph node radiation after mastectomy or whole-breast radiation and lymph node radiation after lumpectomy
People had similar outcomes whether they received lymph node radiation or not.
This analysis was done 10 years after the first person joined the study.
Five years after surgery:
91.8% of people who didn’t receive lymph node radiation had no recurrence, meaning the cancer didn’t come back
92.7% of people who received lymph node radiation had no recurrence
Distant recurrence rates – the cancer coming back in a part of the body away from the breast – and overall survival rates – how long the people lived whether or not the cancer came back – also were similar between the two groups.
“Our findings suggest that down-staging cancer-positive regional lymph nodes with neoadjuvant chemotherapy can allow some patients to skip adjuvant [lymph node radiation] without adversely affecting oncologic outcomes. We are continuing to follow the patients to make sure the results continue,” Dr. Mamounas said.
Dr. Mamounas said the results will change practice at his institution.
Kate Lathrop, MD, of UT Health San Antonio, who is also program director of the San Antonio Breast Cancer Symposium, moderated the media briefing on the research and noted that the study was very important.
“This is a big study and will change a lot of opinions on how to treat patients that have a pathologic complete response to neoadjuvant chemotherapy,” she said.
A pathologic complete response, or pCR, means that no cancer is found during surgery after neoadjuvant chemotherapy.
What this means for you
The results of this study are likely to change treatment for people diagnosed with early-stage, node-positive breast cancer that becomes node-negative after chemotherapy before surgery.
Dr. Mamounas said that while people who have lumpectomy will benefit from the outcomes of this study, people who have mastectomy would likely benefit the most from the results. For them, if the cancer becomes node-negative, no radiation at all would be needed after mastectomy. People who have mastectomy with reconstruction also have a higher risk of developing complications after radiation, so eliminating radiation would have an additional benefit for them.
“I think people should definitely talk to their doctors about this study and ask if they can skip nodal radiation if they meet the criteria we established in this study,” he concluded.
Updated on August 7, 2025