THURSDAY, Dec. 7, 2023 (HealthDay News) -- Patients who present with breast cancer with axillary node involvement (cN+) who are found to be pathologically node-negative at surgery (ypN0) after neoadjuvant chemotherapy can avoid regional nodal irradiation (RNI), according to a study presented at the annual San Antonio Breast Cancer Symposium, held from Dec. 5 to 9 in San Antonio.
Eleftherios (Terry) Mamounas, M.D., M.P.H., from the University of Central Florida in Orlando, and colleagues conducted a trial enrolling 1,641 patients to examine whether adjuvant RNI including the chest wall after mastectomy or addition of RNI to whole breast irradiation after breast-conserving surgery (BCS) improves the invasive breast cancer recurrence-free interval (IBC-RFI) in patients who present with cN+ who are ypN0 at surgery after neoadjuvant chemotherapy. Patients were randomly assigned to no RNI versus RNI after BCS. The primary event analysis included 1,556 patients.
The researchers found that at the time of the analysis, 109 IBC-RFI events were confirmed (59 with no RNI versus 50 with RNI). Between the groups, there was no statistically significant difference observed for IBC-RFI, with five-year point estimates of 91.8 and 92.7 percent for no RNI and RNI, respectively. No significant between-group differences were seen for secondary end points.
"Our findings suggest that downstaging cancer-positive regional lymph nodes with neoadjuvant chemotherapy can allow some patients to skip adjuvant RNI without adversely affecting oncologic outcomes," Mamounas said in a statement. "Follow-up of patients for long-term outcomes continues."
Mamounas disclosed ties to the biopharmaceutical industry.