Accuray Incorporated announced 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 tumour, defined as preventing the growth of the pancreatic tumour, 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 tumour.

Importantly, in all patients treated with the 25 Gy dose, the pancreatic tumour stopped growing or decreased in size, achieving the goal of local tumour control. With the lower doses of 15 Gy and 20 Gy, some patients had continued growth of their pancreatic tumour. 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 tumour 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 tumour," said Dr. Koong.

Used for several decades in the treatment of brain tumours, radiosurgery involves the precise delivery of high doses of radiation to non-invasively ablate tumours and other lesions. Recent technological advances, including the use of real-time imaging to determine the exact position of the tumour during treatment, have now made radiosurgical treatment possible for tumours 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.