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ASCO 2013: Less Lymphedema with Axillary Radiotherapy than Node Dissection, but Comparable Disease Control

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Key Points

  • A European phase III clinical trial found that lymphedema was twice as common among women with sentinel lymph node–positive early breast cancer who had axillary lymph node dissection compared to those who had axillary radiotherapy.
  • Overall and disease-free survival 5 years after treatment were equivalent.
  • Axillary radiotherapy can be combined with radiotherapy received by women who have chosen breast conservation surgery.

A European phase III clinical trial found that lymphedema was twice as common among women with sentinel lymph node–positive early breast cancer who had axillary lymph node dissection compared to those who had axillary radiotherapy. Overall and disease-free survival 5 years after treatment were equivalent.

This study suggests that for patients who need axillary lymph node treatment, axillary radiotherapy is a good alternative to axillary lymph node dissection and can reduce the risk of lymphedema, without diminishing patients’ survival. Axillary radiotherapy can be combined with radiotherapy received by women who have chosen breast conservation surgery.

“I am sure these findings will lead to many doctors rethinking their strategy for treating patients who have a positive sentinel lymph node biopsy,” said lead study author Emiel J. Rutgers, MD, a surgical oncologist at the Netherlands Cancer Institute in Amsterdam. “Lymphedema is a serious concern for patients and a side effect that can affect their quality of life indefinitely.” Dr. Rutgers presented the study findings at the 2013 ASCO Annual Meeting (Abstract LBA1001).

Low Overall Recurrence

The study, called AMAROS, enrolled 4,806 patients with early-stage, invasive, clinically node-negative breast tumors up to 5 cm. Of those patients who had a positive sentinel lymph node biopsy, 744 were randomly assigned to axillary lymph node dissection and 681 to axillary radiotherapy. The median follow-up period was 6.1 years. “The two treatment arms were comparable regarding age, tumor size, grade, tumor type, and adjuvant systemic treatment,” the researchers reported.

The 5-year breast cancer recurrence rates in the axillary nodes after a positive sentinel node biopsy were very low overall, just 0.54% (4/744) after axillary lymph node dissection and 1.03% (7/681) after axillary radiotherapy. By comparison, the axillary recurrence rate after a negative sentinel lymph node biopsy was 0.8% (25/3131).

There were no significant differences between treatment arms regarding estimated 5-year overall survival, which was 93.27% in the axillary lymph node dissection group and 92.52% in the axillary radiotherapy group (P = .3386), and disease-free survival, which was 86.90% in the axillary lymph node dissection group and 82.65% in the axillary radiotherapy group (P = .1788).

Striking Differences in Lymphedema

In contrast, there were striking differences in the numbers of patients who experienced lymphedema. In the first year, 40% of patients undergoing axillary lymph node dissection had lymphedema compared to 22% undergoing axillary radiotherapy (P < .0001). In subsequent years, the number of patients with lymphedema decreased, but the trend persisted. At 5 years, the rates were 28% for the axillary lymph node dissection group and 14% for the axillary radiotherapy group (P < .0001). Dr. Rutgers said that the investigators planned to extend follow-up through 10 and perhaps 15 years.

“We measured the shoulder movement in all patients at 1 year, 3 years, and 5 years,” Dr. Rutgers also reported. “At 1 year, there was some trend of impairment of shoulder function in those patients who received radiotherapy, but this completely disappeared after 3 years and 5 years,” he said.

Rethinking Locoregional Management

“While some controversy continues regarding the role of complete axillary lymph node surgery, this trial presents an important nonsurgical option for selected patients to reduce breast cancer recurrence under the arm and substantially reduce the risk of arm swelling, which is too common and often debilitating for our patients,” said Andrew D. Seidman, MD, Attending Physician for the Breast Cancer Medicine Service at Memorial Sloan-Kettering Cancer Center, New York.

“It is really incredible how quickly it seems in the last few years we are rethinking the locoregional management of breast cancer, less surgery, and perhaps now an increased consideration for the role of radiotherapy for local control,” Dr. Seidman said.

Whether the data on axillary radiotherapy are practice changing “will remain to be seen over the next few months when people have a chance to critically review the data,” Dr. Seidman said. “Extensive surgery in the axilla can be a particular problem for certain selected patients who have medical comorbidities and I suspect, that at least initially, radiation therapy will be used selectively and thoughtfully based on these data.”

This research was supported in part by the European Organisation for Research and Treatment of Cancer Charitable Trust.

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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