Shaped-beam radiation therapy appears to be a promising therapy for life-threatening liver tumors that are prone to spread, says a new preliminary study.1 A team of researchers at the University of Rochester Medical Center reported an 88% success rate in controlling the tumors using this type of radiation therapy.
What is Radiation Therapy?
Radiation is a beam or field of intense energy that is targeted to a certain area or organ in the body. It can be generated by a radioactive substance, such as cobalt, or with an atomic particle accelerator. In some instances, the radioactive substance, such as radioactive iodine, is injected into a vein and travels to the site of the cancer. Radioactive implants are also placed directly into the cancer.
Radiation therapy is effective because it specifically targets and kills cancer cells. This type of treatment is used for many different types of cancer, including liver cancer.2
Precision is the Key Attribute
Shaped-beam radiation therapy, originally designed to treat brain cancers, is a form of very precise radiation. The beam is targeted directly to the liver tumor, rather than targeting the radiation over the entire liver, explained Alan Katz, MD, the study's lead researcher.
"Radiation therapy has not been a recommended treatment for liver metastases [cancers prone to spreading] because of the poor results when whole-liver radiation was used," said Katz, who is an assistant professor of Radiation Oncology at the University of Buffalo. "High-dose, precision radiation therapy is proving to be a promising therapy for metastatic liver disease, and provides an effective treatment option for patients who previously didn't have any."
Challenges of Classic Radiation Therapy
Typically, radiation therapy has been difficult to use as a treatment for liver tumors because they are difficult to target as the organ moves during breathing. That's why this form of very precise radiation therapy helps deliver a high dose of radiation precisely to the tumor, while avoiding damage to nearby healthy tissue, Katz explained. Shaped-beam radiation is also known as steerotactic body radiation therapy.
Katz and a team of colleagues presented preliminary findings of their research using shaped-beam radiation therapy on a group of patients diagnosed with liver cancer. In all, 72 patients with metastatic liver tumors were recruited for the trial. Most of them had colorectal, breast, lung, genitourinary, esophageal, and ovarian cancers that had spread to their livers.
Over a three-year period, the patients underwent shaped-beam radiation as a therapy for their liver cancer. Afterwards, Katz's group followed each patient for a year, on average. Some patients, however, were followed for as long as three years.
On average, they found that patients survived for more than a year, which is twice as long as they would have survived otherwise, Katz and his associates reported. "This is remarkable," Katz said. "For people who are facing this deadly disease, doubling the length of survival brings hope to our patients, and that is so important."
1. American Society for Therapeutic Radiology and Oncology. 47th Annual Meeting. 2005 Oct 16-20. Denver, CO.
2. The Merck Manual. Cancer. Prevention and Treatment of Cancer. Radiation Therapy. Available at: http://www.merck.com/mmhe/sec15/ch182/ch182c.html?qt=shaped%20beam%20radiation%20therapy&alt=sh. Accessed October 27, 2005.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include overseeing health news coverage for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
