Recurrence Rates Higher With Axillary Lymph Node Biopsy After NAT Chemotherapy

Patients with ypN1mi disease based on sentinel lymph node biopsy (SLNB) results treated with nodal radiotherapy should not receive axillary lymph node dissection (ALND), according to an observational study (NCT06529302) published in The Lancet Oncology.

At a median follow-up of 3.1 years, there were 0.4% isolated axillary recurrences, 2.1% axillary recurrences, and 15.8% invasive recurrences out of 1585 cases. The rate of axillary recurrence at 3 years was 0.3%, and a statistical significance was noted in any axillary recurrence across tumor subtypes.

The 3-year recurrence rate was 2.0% (95% CI, 1.3%-2.9%). Across the different subtypes, the 3-year recurrence rate for patients who have hormone receptor (HR)–positive, HER2-positive disease was 0.42% (95% CI, 0%-2.20%); HR-positive, HER2-negative disease was 1.3% (95% CI, 0.7%-2.4%); HR-negative, HER2-positive disease was 3.2% (95% CI, 1.0%-7.5%); and HR-negative, HER2-negative disease was 5.2% (95% CI, 2.9%-8.5%). The P value for the subgroups was less than .0001.

The 3-year recurrence rate for patients who received ALND was 1.7% (95% CI, 0.9%-2.9%) vs 2.3% (95% CI, 1.4%-3.7%) for those who did not. The P value was 0.92. Among patients with triple-negative breast cancer, the 3-year recurrence rate among those who received ALND was 2.4% (95% CI, 0.7%-6.5%) compared with 8.7% (95% CI, 4.4%-15.0%) for those who did not. The P value was .018.

The 5-year rate of any recurrence was 2.7% (95% CI, 1.8%-3.8%), and for isolated axillary recurrence, it was 0.49% (95% CI, 0.19%-1.10%). For those who received ALND, the 5-year recurrence rate was 3.1% (95% CI, 1.7%-5.1%) vs 2.3% (95% CI, 1.4%-3.7%) for those who did not receive ALND. For those with isolated axillary recurrence and who received ALND, the 5-year recurrence rate was 0.5% (95% CI, 0.1%-1.6%) vs 0.5% (95% CI, 0.2%-1.3%) for those who did not receive ALND.

“This large multicenter cohort study provides evidence that ALND might not confer oncological benefit for most patients with residual micrometastases after neoadjuvant chemotherapy. Although current guidelines recommend completion of ALND for all patients with residual micrometastases and macrometastases after neoadjuvant chemotherapy, in the present study, ALND was omitted for almost half (781 [49.3%]) of 1585 patients,” Giacomo Montagna, MD, assistant attending breast surgeon at Memorial Sloan Kettering Cancer Center and lead study author of the manuscript, wrote in the paper with colleagues.

A total of 1585 patients were enrolled in the trial between January 1, 2013, and May 31, 2023. Patients enrolled had residual micrometastases that were detected on SLNB, targeted axillary dissection, or the procedure of marking the axillary lymph nodes with radioactive iodine seeds. The primary end point was any axillary recurrence and stratified by axillary surgery. Secondary end points included rates of locoregional recurrence and invasive recurrence and the proportion of additional positive lymph nodes for those who underwent ALND.

ALND recipients accounted for 50.7% of the study population. The median patient age was 48 years, 58.4% of patients had cT2 disease, 66.5% had node-positive disease, and 79.9% had regional nodal irradiation. Tumor subtypes included 51.0% being HR positive and HER2 negative, 31.1% being HER2 positive, and 17.9% having triple-negative disease. Overall, 61.1% of patients were White and 64.9% of patients were located outside of North America. Additionally, 51.7% of patients received a mastectomy, followed by 48.1% having breast-conserving surgery, and 18.3% having no surgery.

There were 804 patients who underwent ALND, with positive nodes being identified in 30.5%, 8.2% having isolated tumor cells, 50.2% having micrometastases, and 41.6% having macrometastases. The study noted there was a positive correlation between the number of sentinel lymph nodes with micrometastases and the number of additional positive lymph nodes identified at ALND.

Reference

Montagna G, Alvarado M, Myers S, et al. Oncological outcomes with and without axillary lymph node dissection in patients with residual micrometastases after neoadjuvant chemotherapy (OPBC-07/microNAC): an international, retrospective cohort study. Lancet Oncol. 2026;27(1):57-67. doi:10.1016/S1470-2045(25)00598-4