Study finds Gamma Knife radiosurgery alone yields equal survival outcomes for patients with two to 10 tumors

NEW YORK, May 13, 2014 /PRNewswire/ -- A Japanese multi-institutional study¹ of 1,194 patients, has found that individuals with five to 10 tumors treated with Gamma Knife® stereotactic radiosurgery alone (no whole brain radiation therapy) fared as well as a group with two to four tumors who received this radiosurgery-only treatment. The study on survivability after Gamma Knife radiosurgery was published online in The Lancet Oncology on March 10.

According to principle investigators Masaaki Yamamoto, MD and Toru Serizawa, MD, these findings challenge the practice of inconsistent use of radiosurgery in patients with five or more brain metastases, for whom WBRT is often administered.  Neurocognitive deficits are a well-known side effect of WBRT.

"The study provides evidence in favor of offering Gamma Knife radiosurgery as the frontline treatment to patients with more than four brain mets," Dr. Yamamoto says. "It also provides a compelling reason to revise current guidelines for the management of these patients."

He adds that an ongoing prospective randomized study by The North American Gamma Knife Consortium could reinforce the implications of their study. The consortium is exploring neurocognitive outcomes in patients either treated with Gamma Knife alone or with whole brain radiation therapy for five or more brain mets (NCT01731704). The results are expected to further confirm the role of Gamma Knife radiosurgery without WBRT versus only WBRT for multiple brain mets.

Equal overall survival
The prospective observational study, completed by the Japanese Leksell Gamma Knife (JLGK) Society recruited 1,194 participants with one to as many as 10 brain mets from 23 hospitals in Japan. All patients were treated with single-session radiosurgery using Leksell Gamma Knife.

Median overall survival after Gamma Knife radiosurgery in all patients was 12 months. Median overall survival post-treatment was 13.9 months for patients with a single lesion. In both the 2-4 mets group and 5-10 mets group, median overall survival times were 10.8 months.

According to Dr. Yamamoto, "these results suggest that Gamma Knife radiosurgery without WBRT as the initial treatment for patients with five to 10 brain metastases is 'non-inferior' to stereotactic radiosurgery without WBRT in patients with two to four brain metastases – in terms of overall survival and most of the secondary endpoints.

"The essential criticism of employing Gamma Knife radiosurgery without WBRT for patients with several lesions is that microscopic tumors might go untreated, necessitating salvage stereotactic radiosurgery or an alternative therapy," he adds. "Thus, WBRT is widely advocated. However, a recent study showed that WBRT is only able to prevent the emergence of new tumors for no more than six months post-treatment. Many patients with brain mets can survive for more than a year, thereby outliving the effects of WBRT."

Penny K. Sneed, MD, Professor and Vice Chair, Department of Radiation Oncology, University of California, San Francisco, remarks that the multicenter research is an "important prospective study confirming what many Gamma Knife users have observed retrospectively for many years – that the number of brain metastases beyond a single lesion is not very important for survival time, local recurrence, or toxicity, as long as the total tumor volume is limited."    

1.     Yamamoto M, Serizawa T, Shuto T, et al. Stereotactic radiosurgery for patients with multiple brain metastases (JLGK0901): a multi-institutional prospective observational study. The Lancet Oncol 2014:15:387-395

For further information, please contact:
Gert van Santen, Group Vice President Corporate Communications, Elekta AB
Tel: +31 653 561 242, e-mail: [email protected]
Time zone: CET: Central European Time

Raven Canzeri, Global Public Relations Manager, Elekta
Tel: +1 770-670-2524, e-mail: [email protected]
Time zone: ET: Eastern Time

About Elekta
Elekta is a human care company pioneering significant innovations and clinical solutions for treating cancer and brain disorders. The company develops sophisticated, state-of-the-art tools and treatment planning systems for radiation therapy, radiosurgery and brachytherapy, as well as workflow enhancing software systems across the spectrum of cancer care. Stretching the boundaries of science and technology, providing intelligent and resource-efficient solutions that offer confidence to both health care providers and patients, Elekta aims to improve, prolong and even save patient lives.

Today, Elekta solutions in oncology and neurosurgery are used in over 6,000 hospitals worldwide. Elekta employs around 3,500 employees globally. The corporate headquarters is located in Stockholm, Sweden, and the company is listed on the Nordic Exchange under the ticker STO:EKTAB. Website: www.elekta.com. 

SOURCE Elekta