Tuesday, November 01, 2005

Cyberknife Surgery Shows Promise in Spinal Metastases

PARIS, FRANCE - Cyberknife image-guided radiosurgery is effective and generally safe for managing spinal metastases, according to data announced on October 31st at the 13th Annual Meeting of the European Cancer Conference (ECCO).

Iris Gibbs, MD, Assistant Professor of Radiation Oncology, Stanford University Medical Center, Stanford, California, United States, described results obtained in 103 spinal metastases treated using Cyberknife image-guided radiosurgery.

The Cyberknife is a unique image-guided frameless stereotactic radiosurgery delivery system that consists of a lightweight linear accelerator mounted on a robotic arm. Real-time imaging allows for patient movement tracking with 1-mm spatial accuracy. The Cyberknife System is approved by the FDA to provide radiosurgery for lesions anywhere in the body when radiation treatment is indicated.

Dr. Gibbs and colleagues enrolled 74 patients; 84% were symptomatic, 92% received previous treatment, including 74% who received prior radiotherapy.

Using the Cyberknife inverse treatment planning algorithm, the researchers generated treatment plans of 16-25 Gy in 1-3 fractions. The limited volume of the spinal cord receiving greater than 8 Gy in a single fraction to less than 0.3 cm3. When this could not be achieved, the dose was fractionated in two to three fractions.

Patients were followed clinically and radiographically for at least 3 months or until they died. Pain was assessed using a visual analog scale.

After a mean follow-up of 9 month, 36 patients were alive and 38 were dead. No deaths were treatment-related.

Fifty (84%) of 62 symptomatic patients experienced improvement or resolution of symptoms after treatment.

There were three cases of treatment-related spinal cord injury.

Dr. Gibbs cautioned that the ease of radiosurgical treatment and its effectiveness in alleviating pain must be balanced against the possibility of spinal cord injury, especially for lesions of the thoracic spine.

By: Jill Stein