AMSTERDAM – Axillary radiotherapy appears to be a safe and effective alternative to completion axillary lymph node dissection (cALND) for selected patients who have early invasive breast cancer with sentinel lymph node metastasis, a randomized phase III trial showed.
After a mean of just over 8 years of follow-up, there were no significant differences in breast cancer recurrence, overall survival (OS), disease-free survival (DFS), or breast cancer deaths between patients treated with cALND or axillary radiotherapy, reported Akos Savolt, MD, PhD, of the National Institute of Oncology in Budapest.
“This trial has changed our everyday practice about the optimal care of the axilla,” he said at an annual congress sponsored by the European Cancer Organisation.
An estimated 25%-50% of patients with positive sentinel lymph nodes will have disease that extends to other lymph nodes, and for these patients, cALND is the standard of care.
But patients for whom metastasis is limited to the sentinel lymph node are unlikely to benefit from more extensive dissections, and for these patients, the proven benefits of cALND must be weighed against the significant complications associated with the procedure, including lymphedema, arm pain, nerve injury, shoulder dysfunction, and paresthesias, Dr. Savolt noted.
The OTOASOR (Optimal Treatment of the Axilla – Surgery or Radiotherapy) trial was a single-center study designed to see whether axillary radiotherapy could be noninferior to cALND for preventing recurrence and breast cancer deaths.
From mid-2002 through mid-2009,the investigators enrolled women with primary invasive breast cancer (tumors 3 cm or smaller and no clinically detected lymph node metastases), and randomized them prior to surgery to receive either cALND or axillary radiotherapy at a dose of 50 Gy. Patients also received adjuvant therapy as per institutional guidelines.
A total of 474 patients were evaluable for follow-up: 244 assigned to cALND and 230 assigned to radiotherapy. In all, 94 patients assigned to cALND (38.5%) were found to have additional lymph node metastases.
At a mean follow-up of 97 months, 2% of women in the cALND group had experienced an axillary recurrence (the primary endpoint), compared with 1.7% in the axillary radiation arm.
Overall survival was also similar between the groups, at 77.9% vs. 84.8%, respectively, as was disease-free survival, at 72.1% and 77.4%; neither comparison yielded statistically significant results.
There were also no between-group differences in the percentage of patients alive with recurrence, breast cancer deaths (13.9% of patients in the cALND arm vs. 8.7 in the radiation arm), or deaths from other causes (8.2% vs. 6.5%, respectively).
In contrast, however, 15.3% of patients assigned to cALND reported lymphedema, paresthesia, swelling, arm pain, or shoulder mobility problems, compared with 4.7% treated with radiotherapy. There were no significant differences in quality of life as assessed by standard instruments, however.
The study was supported by the Hungarian National Institute of Oncology. Dr. Savolt and colleagues reported no competing interests.