Regional Nodal Irradiation May Be Unnecessary for Some Patients With Breast Cancer Who Receive Neoadjuvant Chemotherapy

By: Chris Schimpf, BS
Posted: Wednesday, January 10, 2024

Some patients whose breast cancer converts from lymph node–positive to lymph node–negative disease after receiving neoadjuvant chemotherapy may not need to undergo adjuvant regional nodal irradiation, according to research presented at the 2023 San Antonio Breast Cancer Symposium (SABCS; Abstract GS02-07). Terry P. Mamounas, MD, MPH, of the University of Central Florida and the Orlando Health Cancer Institute, and colleagues found that skipping adjuvant regional nodal irradiation did not increase the risk of disease recurrence or death 5 years after surgery within this patient population. Follow-up for long-term outcomes from this phase III NRG Oncology/NSABP B-51/RTOG 1304 clinical trial continues.

“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),” noted Dr. Mamounas. “Our findings suggest that downstaging cancer-positive regional lymph nodes with neoadjuvant chemotherapy can allow some patients to skip [the treatment] without adversely affecting oncologic outcomes.”

A total of 1,641 patients diagnosed with lymph node–positive, nonmetastatic breast cancer whose lymph nodes were found to be cancer-free after neoadjuvant chemotherapy and who had undergone either mastectomy or breast-conserving surgery were enrolled in the study. Of the 1,556 patients who were available for primary-event analysis, 92.7% of those who received regional nodal irradiation were free of invasive breast cancer recurrence 5 years after surgery, compared with 91.8% of those who did not. Distant recurrence and overall survival rates were also similar: 93.4% of patients in both groups were free from distant recurrence 5 years after surgery, and 93.6% of those who received regional nodal irradiation were alive after 5 years vs 94% of those who did not.

Disclosure: For full disclosures of the study authors, visit atgproductions.net.

2023 San Antonio Breast Cancer Symposium