Researchers in California say a new form of radiation therapy is showing promise for offering women with early-stage breast cancer an easier, less toxic alternative.

A study involving 50 women who had been diagnosed with early invasive breast cancer and had undergone a lumpectomy to remove the tumor was aimed at evaluating a type of radiation therapy known as “proton beam” radiation.

Instead of undergoing standard radiation treatment that radiates the entire breast, proton beam radiation is targeted much more precisely, enabling doctors to deliver much higher doses with each treatment. That reduces the treatment time from about seven weeks to only two weeks and minimizes side effects.

In the study, which was presented last fall at a meeting of the American Society for Radiation Oncology and will be published in the journal Clinical Breast Cancer this summer, researchers at the Loma Linda University Medical Center said Tuesday that disease-free survival rates at five years among the women receiving the therapy was over 90 percent and that the overall survival rate was close to 100 percent. Patients reported virtually no side effects.

“The study results show that we are able to offer early stage breast cancer patients a treatment program that is less risky and can be completed in less time,” said David Bush, vice chairman of the hospital’s department of radiation, in a statement. “The size of the radiation area is reduced significantly, lessening radiation exposure to the heart, lungs and other parts of the body.”

Researchers have begun testing proton beam radiation, originally developed to treat brain cancer, for other forms of cancer. Some experts have expressed concern, however, that some hospitals are starting to use the approach before sufficient research has been done to show that it is at least as effective as standard radiation. Some have also expressed concern that the costly equipment to deliver the treatment is encouraging doctors to steer patients to the therapy before it has been proven.

In their paper, the researchers acknowledge that the findings “would need to be confirmed in comparative trials.”

For a video about the treatment, click here.