For breast cancer patients with a positive sentinel node biopsy (SNB), skipping axillary lymph node dissection (ALND) in favor of axillary radiotherapy (ART) results in similar outcomes without the harmful side effects of surgery, according to the results of the AMAROS trial reported at the American Society of Clinical Oncology meeting in Chicago.

“ALND and ART after a positive SNB provide excellent and comparable regional control,” wrote Emiel Rutgers, MD, of the Netherlands Cancer Institute in Amsterdam, and colleagues in the study abstract. “ART reduces the risk of short-term and long-term lymphedema compared to ALND.”

Between 2001 and 2010, more than 4,800 women were entered into the trial and randomized between ALND and ART in case of positive SNB. A total of 744 in the ALND arm and 681 in the ART arm had positive SNB, 60 percent with a macrometastasis.

After a median follow up of 6.1 years, results showed five-year recurrence rates were 0.5 percent and 1 percent in the ALND and ART arms, respectively.

There were no significant differences in overall survival and disease-free survival between treatment arms, according to Rutgers and colleagues.

The major difference between treatments came in the form of lymphedema rates. This obstructive condition was found in 40 percent and 28 percent of ALND patients at one year and five years, respectively. In contrast, rates of lymphedema in ART patients were 22 percent after one year and 14 percent after five years.

Swelling was slightly better in the ART group and movement was better in the ALND group, though these differences were not statistically significant, according to the researchers.

Currently, in cases of positive SNB, the standard of care is ALND.