"While stereotactic radiosurgery for the treatment of benign brain tumors has become widely accepted, our knowledge about the use of this technology for benign tumors outside the brain has been limited," said Steve Burton, M.D., study co-author and assistant professor, department of radiation oncology, University of Pittsburgh School of Medicine. "The results of our study indicate that treating these tumors with CyberKnife is safe and effective and can successfully control their growth and progression."
The study, whose purpose was to evaluate the feasibility, toxicity and local control of patients with symptomatic benign tumors treated with CyberKnife, evaluated 50 benign tumors in 35 patients who underwent radiosurgery between 2001 and 2004 at the University of Pittsburgh Medical Center. The tumors were located in the spine (36), neck (6), skull (3), eye (3) and brainstem (2). Seventy-eight percent of patients treated with CyberKnife experienced an improvement in their pre-treatment symptoms, which included pain and weakness. The local control rate – the rate at which the tumor's growth was controlled locally – was 96 percent for the 26 patients who underwent follow-up imaging from one to 25 months after the treatment was administered.
"Our findings demonstrate that CyberKnife may offer a promising treatment option for patients with benign tumors who are not candidates for surgery or whose tumors are not amenable to surgery," said Dr. Burton. "The potential benefits are significant and include short-term treatment time in an outpatient setting with rapid recovery and symptomatic response." Dr. Burton added that follow-up studies will seek to assess the long-term tumor control rates as well as any future effects.
"This study represents the largest to date on the use of frameless radiosurgery to treat benign extra-cranial lesions, and the results thus far are very encouraging. Of noteworthy interest, CyberKnife was able to control aggressive benign tumors that had progressed despite surgery and/or conventional radiation," said Ajay Bhatnagar, M.D., resident, department of radiation oncology, University of Pittsburgh School of Medicine.
CyberKnife is a non-invasive robotic radiosurgical device that can remove tumors and other lesions without open surgery, using a robotic arm, controlled by a computer, that sends multiple beams of high-dose radiation directly to the tumor site.
Also involved in the study from the University of Pittsburgh were Peter Gerszten, M.D, department of neurological surgery; Anurag Agarwal, M.D., department of radiation oncology; C.W. Ozhasoglu, M.D., department of radiation oncology; William Vogel, R.T.T., department of radiation oncology; W.C. Welch, M.D., department of neurological surgery; and Shalom Kalnicki, M.D., now of the department of radiation oncology, Montefiore Medical Center, New York.