Radiotherapy Trumps Lymph Node Dissection in Breast Cancer

Roxanne Nelson

May 02, 2014

For breast cancer patients with a positive sentinel node, axillary radiotherapy (ART) might be a better option than surgery to remove the nodes because it is associated with less morbidity and fewer complications, according to new data.

The results come from a large international trial — dubbed AMAROS (After Mapping of the Axilla: Radiotherapy or Surgery?) — conducted in 4806 breast cancer patients randomized to either ART or axillary lymph node dissection (ALND).

One year and 5 years after treatment, lymphedema was less common in patients treated with ART than in those treated with either ALND or with both therapies.

These findings could change surgical guidelines and offer patients a better quality of life, said lead author Mila Donker, MD, from the Netherlands Cancer Institute and Antoni van Leeuwenhoek Hospital in Amsterdam. She was speaking at a press briefing held in advance of the American Society of Breast Surgeons (ASBS) 15th Annual Meeting in Las Vegas.

"The baseline surgical complication rate was, on average, 2.5 times higher in patients undergoing a lymph node dissection than in patients treated with radiotherapy to the axilla," Dr. Donker reported. "Lymphedema at 5 years was 2 times higher in patients treated with lymph node dissection than in those who received radiotherapy."

In the patients who received combination lymph node dissection and radiotherapy, lymphedema was 5 times higher than in patients who received radiotherapy only.

 
These data strongly support radiotherapy as the preferred treatment.
 

"These data strongly support radiotherapy as the preferred treatment," she said, and the combination of ART and ALND should, if possible, be avoided.

"We are doing fewer and fewer axillary dissections and we are trying to get away from axillary surgery because of the complication rate," said press briefing moderator Deanna Attai, MD.

"This is a nice demonstration that we do have alternatives to reduce local recurrence rates using radiation therapy, and showing that we can safely avoid surgery in some of these patients," she explained. Dr. Attai is a breast surgeon from Burbank, California, and chair of the communications committee and a member of the ASBS board of directors.

Findings from the AMAROS trial were presented last year at the annual meeting of the American Society of Clinical Oncology, as reported at that time by Medscape Medical News.

At the ASBS press briefing, Dr. Donker explained the rationale for the study.

Sentinel node biopsy is standard for evaluating axillary lymph node status in cN0 breast cancer patients. If treatment is advised after a positive biopsy, ALND is currently the standard of care. Although patients can achieve excellent results with this treatment, it is associated with adverse events.

The AMAROS researchers set out to test the hypothesis that ART would give comparable regional control with a lower rate of adverse effects.

Of patients with positive lymph nodes, 744 were assigned to the ALND group and 681 to the ART group.

The 5-year recurrence rate was 0.43% in the ALND group and 1.19% in the ART group. "This difference did not reach statistical significance, and the trial was underpowered to reach the primary end point," said Dr. Donker.

Higher Rates of Complications and Lymphedema

Dr. Donker and colleagues found that the incidence of surgical complications (infection, hemorrhage, early edema, and persistent seroma) was significantly higher in the ALND group than in the ART group (23% vs 9%; P < .001). However, the incidence of paraesthesia of the arm was similar in the ALND and ART groups (10% vs 9%).

At 1 year, lymphedema was less common in patients treated with ART than with ALND (15% vs 25%; < .001) or with both therapies (15% vs 59%; P < .001).

At 5 years, lymphedema was less common in patients treated with ART than with ALND (10% vs 21%; < .001) or with both therapies (10% vs 58%; P < .001).

The independent risk factors for the development of lymphedema in the first year after therapy include treatment with ALND rather than ART (odds ratio [OR], 2.2), treatment with the combination rather than ART alone (OR, 7.6), a body mass index above 25 kg/m², premenopausal status, and treatment on the dominant side.

Dr. Donker noted that shoulder mobility decreased temporarily for women in both treatment groups, particularly during the first year. Patients who received more extensive ALND or specialized supraclavicular radiotherapy after surgery experienced a greater loss of mobility than those who received ART. However, at 1 year, women treated with less extensive ALND had better shoulder movement than those treated with ART.

American Society of Breast Surgeons (ASBS) 15th Annual Meeting. Presented April 30, 2014.

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