Results from a clinical study of CyberKnife ® radiosurgery for locally advanced pancreatic cancer

Accuray Incorporated announced today the publication of the results from a clinical study of CyberKnife ® radiosurgery for locally advanced pancreatic cancer. This study, a collaboration between radiation oncologists, surgeons, and other medical specialists, is the first to demonstrate the feasibility of using stereotactic radiosurgery for the treatment of locally advanced pancreatic cancer. The results were published in the International Journal of Radiation Oncology and Biological Physics, by physicians at Stanford University Medical Center.

The study examined the impact of delivering CyberKnife® radiosurgery to patients with locally advanced pancreatic cancer. The goal was to achieve local control of the tumor, defined as preventing the growth of the pancreatic tumor, without significant side effects from the radiation dose.

Designed as a dose-escalation study, a total of 15 patients, diagnosed with inoperable locally advanced pancreatic cancer, were treated and evaluated. Subsets of patients were treated with three different radiation doses, 15 Gy (3 patients), 20 Gy (5 patients), and 25 Gy (7 patients), in a single treatment session using the CyberKnife® System. Patients were then assessed over a 12-week period for toxicity from the radiation and for growth of their tumor.

Importantly, in all patients treated with the 25 Gy dose, the pancreatic tumor stopped growing or decreased in size, achieving the goal of local tumor control. With the lower doses of 15 Gy and 20 Gy, some patients had continued growth of their pancreatic tumor. Within the follow-up period after treatment, no significant gastrointestinal toxicity was reported for any of the patients treated, at any dose level. The authors conclude that radiosurgery is feasible for patients with locally advanced pancreatic cancer, and local control can be achieved at 25Gy.

“The importance of this study is that it establishes a promising role for CyberKnife® radiosurgery in the treatment of locally advanced pancreatic cancer. The future challenge is to determine the most effective way to incorporate this treatment with other therapeutic strategies,” said Dr. Albert Koong, Assistant Professor of Radiation Oncology at Stanford University Medical Center, and lead author of the study.

Local tumor control is only one clinical end point for patients with pancreatic cancer. Pancreatic cancer has a high rate of metastasis to other organs in the body, so controlling the spread of the disease is important for improving patient survival. “Our next trial, currently underway, combines a CyberKnife® radiosurgical boost treatment with standard chemotherapy and radiotherapy to treat systemic spread of the disease, in addition to local control of the pancreatic tumor,” said Dr. Koong.

Used for several decades in the treatment of brain tumors, radiosurgery involves the precise delivery of high doses of radiation to non-invasively ablate tumors and other lesions. Recent technological advances, including the use of real-time imaging to determine the exact position of the tumor during treatment, have now made radiosurgical treatment possible for tumors throughout the body. Unlike conventional radiation therapy techniques traditionally used to treat pancreatic cancer, CyberKnife® radiosurgery administers a high dose of radiation in a single or small number of treatments, with minimal toxicity to surrounding tissues and organs.

About the CyberKnife® System: The CyberKnife® Stereotactic Radiosurgery System is a non-invasive, 100% frameless image-guided radiosurgery system that can ablate tumors and other lesions anywhere in the body without open surgery. The CyberKnife® System treats in single or staged (typically 2-5) sessions, and monitors internal reference points in the anatomy (skeletal landmarks or small implanted markers) to correct for patient movement in real time during actual treatment. It delivers multiple beams of precisely directed radiation that converge upon the tumor while minimizing injury to surrounding healthy tissue.

The unique CyberKnife® System technology, which was developed in cooperation with Stanford University, was cleared by the FDA in August 2001 and received CE approval in September 2002 to provide radiosurgery for lesions anywhere in the body when radiation treatment is indicated. To date, the CyberKnife® System has been used to treat more than 8,000 patients worldwide. http://www.accuray.com