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Two Forms of Radiosurgery for Brain Metastases Are Equally Effective

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Key Points

  • The Gamma Knife was slightly more effective than RapidArc at focusing the beam of radiation, thus limiting spread to normal tissue.
  • RapidArc offered much quicker treatment compared to the Gamma Knife; Gamma Knife treatment usually took 60–100 minutes, about 3–5 times longer than RapidArc.

While two advanced radiosurgery approaches—Gamma Knife and RapidArc—offer different strengths, they are equally effective at eradicating cancer in the brain, say researchers at Sidney Kimmel Cancer Center at Jefferson.

Their study, published by Liu et al in Frontiers in Oncology, compared the two different devices in brain radiosurgery. Six patients, each with three or four brain metastases, were studied.

Key Findings

The Gamma Knife was slightly more effective than RapidArc at focusing the beam of radiation, thus limiting spread to normal tissue, and RapidArc offered much quicker treatment compared to the Gamma Knife, researchers said. Gamma Knife treatment usually took 60 to 100 minutes, about 3 to 5 times longer than RapidArc.

“In the end, using one or the other doesn't make a significant clinical difference and that is important to know because physicians and patients now know they have a choice of treatments,” said Associate Professor Wenyin Shi, MD, PhD, Codirector of the Jefferson Brain Tumor Program.

Understanding the benefits of advanced radiosurgery technology is essential because there has been, and will continue to be, an increase in cases of brain metastases, said coauthor Adam Dicker, MD, PhD, Chair and Professor of Radiation Oncology, Pharmacology, and Experimental Therapeutics at the Sidney Kimmel Medical College at Thomas Jefferson University.

Study Background

“As drug therapy for cancer becomes better at controlling systemic cancer, disease in the brain increases over time. The brain is a sanctuary for cancer—chemotherapies and targeted agents can't reach the brain and the central nervous system because of the blood-brain barrier,” Dr. Dicker said. “The results are that a number of different cancers are now showing up in the brain.”

Radiosurgery delivers a focused dose of radiation on tumors in order to shrink or kill the cancer, while sparing normal brain tissue. The Gamma Knife, invented in Sweden, features a circular array of 201 beams of gamma radiation that meet at a single point. The downside of the treatment, which is very accurate, is that patients wear a helmet that is fixed to the skull, Dr. Shi said. The procedure can also take a long time, he added.

RapidArc radiation is a type of linear accelerator that emits high-energy photons. Very small beams with varying intensities are aimed at a tumor and then rotated around the patient. This results in attacking the target in a complete three-dimensional manner. A single treatment can take as little as 10 to 15 minutes.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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