New market of extracranial radiosurgery applications reported at Japanese CyberKnife Users' Meeting

Sunnyvale 09 July 2002Japanese physicians recently convened for the second annual Japanese CyberKnife Users' Meeting in Ube, Japan, to share their clinical experience with the CyberKnife Stereotactic Radiosurgery System. One of the highlights at this year's meeting was the increase in interest and experience using the CyberKnife to non-invasively ablate tumours and lesions located outside of the head, in areas such as the spine. This represents a significant achievement because conventional systems limit the use of radiosurgery to the brain.


Patient data shared at the Japanese Users' Meeting show that as of May, 2002, more than 3000 patients worldwide have been treated with the CyberKnife, thereby reaching a new milestone. An increasing number of these patients are being treated for extracranial lesions. 491 patients or sixteen percent of CyberKnife patients were treated for lesions located in extracranial sites. Cases reported included 154 nasopharyngeal carcinoma patients, 256 spinal tumour patients, and 66 lung patients. In Japan, over 340 patients with extracranial lesions have been treated with the CyberKnife.

The latest generation CyberKnife with Dynamic Tracking Software (DTS), released last year, is a non-invasive frameless radiosurgical device which is unique in combining image-guidance and robotics to accurately target tumours located throughout the body. Multiple beams of radiation delivered by a robot-mounted miniature linear accelerator converge upon the target, destroying it while minimising exposure to surrounding healthy tissue. The CyberKnife has been used successfully to treat a wide range of indications, including functional disorders such as trigeminal neuralgia, vascular malformations, and malignant and benign tumours located in either the brain, spine, lung, pancreas, and liver.

The CyberKnife has been well received in Japan, where many of the sites are in the process of upgrading to the DTS system. Currently, there are 15 CyberKnife sites actively treating patients worldwide. Seven CyberKnife sites are operational in Japan and installations at an additional eight Japanese hospitals are currently ongoing. The CyberKnife is distributed in Japan through Meditec Corporation, a wholly owned subsidiary of Marubeni Corporation.

Toshihiko Inoue, M.D., Professor of Radiation Oncology at Osaka University Graduate School of Medicine, stated: "Compared to last year, the number of users participating in the meeting has nearly tripled, from 11 to 32. Over 2000 patients have benefited from the CyberKnife in Japan alone. Some of the most exciting developments include the ability to treat spinal tumours and lung tumours with radiosurgery. These targets have traditionally been impossible to treat with conventional radiosurgical techniques. The preliminary results with the CyberKnife appear very promising for these new areas and are critical to establishing a foundation for future applications of the CyberKnife."

Thierry Thaure, Senior Vice President of Sales and Marketing at Accuray, stated: "The Users' Meeting has been a great forum for discussion and feedback regarding the CyberKnife from our user base in Japan, a country which represents one of the largest medical device markets in the world. We are particularly excited about the preliminary clinical data presented at the meeting for extracranial CyberKnife applications as they represent new markets for radiosurgery."

"The volume of these types of procedures is rapidly growing as clinical acceptance increases. We project that 75 percent of the CyberKnife cases performed five years from now will be extracranial. Radiosurgery outside of the head is now a reality and becoming increasingly accessible to more patients throughout the world as a non-invasive alternative to open surgery." The Worldwide CyberKnife Users' Meeting will be held later this year in the United States.

The unique CyberKnife technology was developed in co-operation with Stanford University and was cleared by the FDA in August, 2001 to provide radiosurgery for lesions anywhere in the body when radiation treatment is indicated. The latest generation CyberKnife system offers proprietary skull and fiducial tracking features. Targets outside of the head are tracked in six dimensions through the use of small fiducials that are percutaneously implanted near the tumour and serve as reference points for tumour location.

During radiosurgical treatment, a proprietary image-guidance system tracks the position of the fiducials. Information about tumour position is communicated to the robotic arm, which can re-position the radiation-generating linear accelerator to compensate for changes in patient position. The CyberKnife is the only radiosurgical system in the world that precisely corrects for patient movement during actual treatment. The level of accuracy achievable by the system allows higher doses of radiation to be used, which provides the potential for greater tumour-killing efficacy and greater likelihood of cure.

More news about the CyberKnife technology is available in the following VMW July 2002 article CyberKnife to ablate brain tumours in infants and children using non-invasive radiosurgery.

Leslie Versweyveld

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