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Axillary Radiotherapy Associated With Fewer Side Effects Than Lymph Node Dissection in AMAROS Analysis

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Key Points

  • An analysis of morbidity from the AMAROS trial found equal clinical outcomes after axillary radiation therapy and axillary lymph node dissection in breast cancer patients with positive nodes, but radiation therapy was associated with fewer side effects
  • Patients in the radiation therapy arm had significantly less lymphedema at 1 and 5 years, and fewer postoperative surgical complications.

Radiation therapy, an emerging treatment modality for breast cancer in the lymph nodes, is associated with significantly fewer postoperative complications than axillary lymph node dissection, according to a detailed analysis of morbidity from the AMAROS trial presented at a press briefing prior to the American Society of Breast Surgeons (ASBS) Annual Meeting in Las Vegas.

Previous studies have shown no difference in survival among women receiving either treatment, but results from this international prospective multicenter trial suggest that radiation therapy has the advantage of producing fewer side effects, said Mila Donker, MD, of the Netherlands Cancer Institute and Antoni van Leeuwenhoek Hospital in Amsterdam.

“Surgical complications were more than twice as high for patients having lymph node dissection, and the rate of lymphedema at 5 years was also twice as high,” Dr. Donker reported.

The AMAROS trial of 4,806 early-stage breast cancer patients randomly assigned those with positive sentinel nodes (n = 1,425) to treatment with axillary lymph node dissection (n = 744) or axillary radiotherapy (n = 681), including the medial part of the supraclavicular fossa. At the ASBS meeting, investigators presented the analysis of morbidity, including the predictive value of treatment factors.

Surgical Complications, Lymphedema Rates Much Higher With Dissection

Patients receiving axillary lymph node dissection group had an overall surgical complication rate of 22.6% vs 9.0% for the axillary radiotherapy group (P < .001). This included higher rates of hemorrhage, postoperative infections, and other conditions.  

Shoulder complications were observed in 23% of the patients in the axillary lymph node dissection group vs 9% in the axillary radiotherapy group (P < .001). Lymphedema at 1 year post-treatment was observed in 25% and 15%, respectively (P < .001) at 1 year, and in 59% of the 27 patients who received both axillary lymph node dissection plus axillary radiotherapy (P < .001 vs axillary radiotherapy). After 5 years, the rates of lymphedema were 21%, 10%, and 58%, respectively (P < .001 for all vs axillary radiotherapy).

The independent risk factors for the development of lymphedema within the first year were treatment with axillary lymph node dissection, which carried more than twice the risk vs axillary radiotherapy, or treatment with the combination, where the risk was more than sevenfold; body mass index > 25 kg/m2, premenopausal status, and treatment on the dominant side also raised the risk for lymphedema. Paresthesia of the arm was observed in 10% of patients after axillary lymph node dissection and 9% after axillary radiotherapy.

Shoulder mobility decreased temporarily, particularly during the first year in both treatment arms. Risk factors for shoulder problems at 1 year included the addition of isolated supraclavicular radiotherapy after axillary lymph node dissection, and more extensive axillary lymph node dissection.

Surgery Not the Only Option

“Our morbidity data strongly supports radiotherapy as the preferred treatment,” Dr. Donker concluded.

Deanna J. Attai, MD, of the Center for Breast Care in Burbank, California, who moderated the press briefing, commented, “We are doing fewer and fewer axillary dissections now, because of the complication rate. This study demonstrates that we do have alternatives for reducing local recurrence rates and can potentially avoid surgery in some patients.”

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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