In an initial analysis of a retrospective cohort study (OPBC-07/microNAC) reported in The Lancet Oncology, Montagna et al found that available evidence did not provide support for axillary lymph node dissection (ALND) in all patients with ypN1mi disease in sentinel lymph nodes after neoadjuvant chemotherapy for breast cancer.
Study Details
The study involved data from institutional databases from 84 cancer centers in 30 countries on patients with clinical T1-4, N0-3 breast cancer at diagnosis. These patients received neoadjuvant chemotherapy and surgery between January 2013 and May 2023 and had residual sentinel node micrometastases (> 0.2 mm or > 200 cells, less than 2.0 mm in size). The primary endpoint was the 5-year rate of any axillary recurrence (isolated or combined with local or distant recurrence) stratified by type of axillary surgery; the current report provides outcomes at 3 years.
Key Findings
Among 1,585 patients included in the analysis, 804 (50.7%) underwent ALND and 781 (49.3%) did not; 925 (58.4%) had cT2 tumors, 1,054 (66.5%) had node-positive disease, and 1,267 (79.9%) received nodal radiotherapy.
Median follow-up was 3.1 years (interquartile range = 1.8–5.2 years). At 3 years, the rate of any axillary recurrence in the entire population was 2.0% (95% confidence interval [CI] = 1.3%–2.9%), including rates of 1.7% (95% CI = 0.9%–2.9%) among those with ALND vs 2.3% (95% CI = 1.4%–3.7%) among those without ALND (P = .92).
Among patients with triple-negative disease, the 3-year rate of axillary recurrence was 8.7% (95% CI = 4.4%–15.0%) among those with no ALND vs 2.4% (95% CI = 0.7%–6.5%) among those with ALND (P = .018).
On multivariable analysis, triple-negative breast cancer (hazard ratio [HR] = 3.83, 95% CI = 1.72–8.52) and omission of nodal radiotherapy (HR = 2.62, 95% CI = 1.19–5.73) were independently associated with increased risk of axillary recurrence. Omission of ALND was not associated with increased risk (HR = 0.86, 95% CI = 0.37–2.00).
The investigators concluded: “Overall, these results do not support ALND for all patients with ypN1mi on sentinel lymph node biopsy treated with nodal radiotherapy; however, tumour biology should be taken into account when considering ALND omission.”
Walter P. Weber, MD, of Breast Center, University Hospital of Basel, Basel, Switzerland, is the corresponding author for The Lancet Oncology article.
DISCLOSURE: The study was funded by the U.S. National Institutes of Health and National Cancer Institute. For full disclosures of the study authors, visit thelancet.com.
