September 25, 2008

Proton Therapy May Prevent Later Cancers

U.S. scientists say proton therapy patients have a two-fold lesser risk of developing a secondary cancer compared with being treated by photon radiation.

Proton therapy involves a specialized type of external beam radiation using protons rather than X-rays to treat cancer.

The first-of-its-kind study, led by Dr. Nancy Tarbell of Massachusetts General Hospital, contradicts theories that proton radiation might increase the incidence of secondary cancers because of what is called scatter radiation, the scientists said.

"This study could have a substantial impact on the care of patients," said Tarbell. "Since cancer patients are surviving for longer periods of time, side effects of therapy are becoming increasingly important for doctors to consider when developing treatment plans. Since this is a retrospective study, however, we will need additional studies to further prove this hypothesis."

Photon radiation is the standard external beam radiation therapy treatment, while proton radiation is a more targeted form of external beam radiation delivering less radiation to bordering normal structures.

The retrospective cohort study was presented this week in Boston during the annual meeting of the American Society for Therapeutic Radiology and Oncology.