WEDNESDAY, April 30 (HealthDay News) -- Radiation therapy may beat surgery for treatment of affected lymph nodes in some breast cancer patients, resulting in fewer postoperative problems, according to a new study.

Researchers compared the two treatment approaches in terms of survival and complications.

Both approaches provide excellent overall results, said study author Dr. Mila Donker, a researcher at the Netherlands Cancer Institute and Antoni van Leeuwenhoek Hospital, in Amsterdam. "With a median follow-up of 6.1 years, no differences were observed in survival," she said.

Previous studies have also found no differences in survival among women getting the two different treatments, she noted.

However, she found those treated with radiation in this study were much less likely to have complications.

Donker is due to present the findings Wednesday at the annual meeting of the American Society of Breast Surgeons, held in Las Vegas. Studies presented at medical meetings are typically viewed as preliminary until published in a peer-reviewed journal.

For the new study, Donker evaluated data from a larger international trial. That study, conducted at many centers, randomly assigned breast cancer patients who had a positive sentinel node (in which cancer was found) to receive one of two treatments. Patients underwent either surgical removal of the node, called "axillary lymph node dissection" or radiation, called "axillary [underarm] radiotherapy."

The sentinel node is the lymph node to which cancer cells are most likely to spread, and there can be more than one.

The larger trial enrolled nearly 5,000 patients between 2001 and 2010. In this new analysis, Donker focused on 820 patients. Of those, 406 got radiation, 387 had surgery and 27 had both treatments.

Surgical complications such as infection or bleeding occurred in 23 percent of the surgery group, compared with 9 percent of the radiation group.

Donker also looked at how many patients got lymphedema -- the painful tissue swelling that can occur after treatments to the underarm. At one year, lymphedema occurred in 15 percent of those who had radiation, 25 percent of those who had surgery and 59 percent of those who had both.

Those most likely to have lymphedema at one year were those who had surgery, those with a body mass index of more than 25 (considered overweight), those who had not yet gone through menopause and those whose treatment was on their dominant side (depending on whether women were right- or left-handed).

Other recent research suggests that radiation therapy is of benefit for breast cancer patients with only a few lymph nodes involved, just as it is known to be for those with four or more positive nodes.

The findings from Donker's study echo some previous research, but also add new information, said Dr. Laura Kruper. She is director of the Cooper Finkel Women's Health Center and co-director of the breast oncology program at the City of Hope Cancer Center, in Duarte, Calif. She reviewed the findings.

It's a bit surprising, she said, that the radiation resulted in less lymphedema, but not surprising that the two together increased the chances of the complication.

While other studies also have found that being overweight is linked with a higher risk of lymphedema, Kruper said the finding that women who have not yet gone through menopause being at higher risk is new.

The new study does leave some questions unanswered, she said, such as the effect of underarm radiation on breast reconstruction results.

More information

To learn more about sentinel nodes, visit the U.S. National Cancer Institute.