A gentler, more targeted type of radiation therapy may help prevent breast cancer from coming back, researchers report.

In a study of 43 women with early-stage breast cancer who underwent the new procedure, none relapsed over the next four years, says Martin Keisch, MD. Keisch is a radiation oncologist at Mount Sinai Comprehensive Cancer Center in Miami Beach, Fla.

There were no serious long-term side effects, and 85 percent of women rated the cosmetic results as “good to excellent,” he tells WebMD.

The study was presented at the annual meeting of the American Society for Therapeutic Radiology and Oncology.

Less Radiation, Fewer Doctor Visits

The researchers studied women with early-stage breast cancer who were undergoing breast-conserving surgery, in which doctors remove only the tumor rather than the entire breast. Most of these women are then given radiation therapy to kill off any cancerous cells that might be left behind.

Traditionally, doctors have used radiation therapy on the entire breast. In contrast, the new procedure, a type of limited-field radiation therapy, targets the radiation to the area of the breast once occupied by the tumor, Keisch says.

There are a handful of advantages to focused therapy, he says.

First and foremost is a lower risk of long-term side effects. “That’s the main reason to do this,” Keisch says. Only about one-fourth as much healthy tissue is exposed to radiation, which can damage healthy cells and even cause secondary cancers years down the road.

Also, women only have to come in for 10 treatments over five days, he says. In contrast, traditional radiation requires treatment for several weeks.

A Gentler Kind of Therapy

When doctors first started using focused radiation, the only way to give it was through implants; catheters filled with radioactive material were implanted into the targeted site of the breast.

“The needles go in one side and out the other,” Keisch says. “Despite excellent results, many women refuse to have it.”

That’s where the new procedure, called balloon brachytherapy, comes in.

“It’s a much simpler way to give focused radiation,” he says. A balloon filled with radioactive seeds is inserted through a catheter to an area of the breast that once housed the tumor.

“It’s a 15-minute procedure that can be done under local anesthesia,” Keisch says.

There are short-term risks -- chiefly burning, inflammation, and tenderness at the site of insertion.

The brachytherapy system, called the MammoSite Radiation Therapy System, was approved by the FDA in 2002.

100 percent Satisfaction With Breast Procedure

Keisch says that 100 percent of the women in the study say they would have the procedure again or recommend it to a family member.

“I’d recommend it to my wife,” he says.

Keisch estimates that about 100,000 of the 200,000-plus American women diagnosed with breast cancer each year are candidates for the procedure.

But other doctors tell WebMD that it's too soon to know whether the new system prevents relapses as well or as safely as the usual several-week course of whole-breast radiation.

Richard Poetter, MD, a radiation oncologist at the University Clinic for Radiotherapy and Radiobiology in Vienna, Austria, says, “Many side effects don’t show up until five or 10 years out. You really need longer-term follow-up.”

Phillip Devlin, MD, of Harvard Medical School, has similar concerns about long-term effectiveness. “We need to see the data in another two years,” he says. “Five years is the traditional benchmark for evaluating a new cancer treatment.”

Keisch says the women will be followed for at least 10 years.

By Charlene Laino, reviewed by Louise Chang, MD

SOURCES: American Society for Therapeutic Radiology and Oncology 47th Annual Meeting, Denver, Oct. 16-20, 2005. Martin Keisch, MD, radiation oncologist, Mount Sinai Comprehensive Cancer Center, Miami Beach, Fla. Richard Poetter, MD, radiation oncologist, University Clinic for Radiotherapy and Radiobiology, Vienna, Austria. Phillip Devlin, MD, assistant professor of radiation oncology, Brigham and Women’s Hospital and Harvard Medical School.