Comparable Disease Control, Less Morbidity With Axillary Radiotherapy vs Surgery in Breast Cancer Patients With Positive Sentinel Node
In a noninferiority phase III EORTC 10981-22023 AMAROS trial reported in The Lancet Oncology, Donker et al found that axillary radiotherapy provided comparable disease control and was associated with less morbidity compared with axillary surgery in breast cancer patients with a positive sentinel lymph node.
Study Details
In this open-label trial, 4,806 breast cancer patients with T1–2 primary unifocal invasive breast cancer with no palpable lymphadenopathy were randomly assigned at 34 centers in nine European countries between February 2001 and April 2010 to receive axillary lymph node dissection or axillary radiotherapy. A total of 1,425 patients had a positive sentinel node, consisting of 744 in the axillary lymph node dissection group and 681 in the axillary radiotherapy group.The primary endpoint was noninferiority of 5-year axillary recurrence, set at ≤ 4% for the radiotherapy group compared with an expected 2% in the dissection group.
Axillary Recurrence
Median follow-up was 6.1 years among patients with positive sentinel lymph nodes. Additional positive nodes were identified in 33% of patients in the dissection group. Axillary recurrence was observed in four patients in dissection group and seven in the radiotherapy group; 5-year axillary recurrence rates were 0.43% (95% confidence interval [CI] = 0.00%–0.92%) and 1.19% (95% CI = 0.31%–2.08%). The noninferiority test was underpowered due to a low number of events; the one-sided 95% CI for the underpowered noninferiority test on the hazard ratio (HR) was 0.00% to 5.27%, with a noninferiority margin of 2%.
Five-year disease-free survival was 86.9% in the dissection group vs 82.7% in the radiotherapy group (HR = 1.18, P = .18). Death due to breast cancer occurred in 7% vs 8%, and 5-year overall survival was 93.3% vs 92.5% (HR = 1.17, P = .34).
Lymphedema
The dissection group had significantly higher rates of lymphedema in the ipsilateral arm at 1 year (28% vs 15%, P < .0001), 3 years (23% vs 14%, P = .003), and 5 years (23% vs 11%, P < .0001) and a higher rate of arm circumference increase ≥ 10% in ipsilateral upper or lower arm at 5 years (13% vs 6%, P = .0009).
The investigators concluded: “Axillary lymph node dissection and axillary radiotherapy after a positive sentinel node provide excellent and comparable axillary control for patients with T1–2 primary breast cancer and no palpable lymphadenopathy. Axillary radiotherapy results in significantly less morbidity.”
Emiel J. T. Rutgers, MD, of Netherlands Cancer Institute, is the corresponding author for the Lancet Oncology article.
The study was funded by the EORTC Charitable Trust. The study authors reported no potential conflicts of interest.
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