Medical Device Daily

Recent studies have found radiosurgery to be an effective treatment option for medically inoperable lung cancer patients as it provides good local control and survival rates. But often times treating these tumors is particularly difficult – because of the movement with respiration. The key in radiosurgery techniques is being as precise as possible without exposing unnecessary parts of the lung to radiation.

Accuray (Sunnyvale, California), which has had significant success before with its radiosurgical application reported that the FDA has granted it 510(k) clearance to market Lung Optimized Treatment, a new component of the CyberKnife VSI System. The 510(k) clearance enables Accuray to provide physicians with greater flexibility in delivering radiosurgery treatments to patients with lung cancer, a common and deadly lung cancer.

“There are other radiation devices that can treat simple tumors in the lung,“ Euan Thomson, PhD, president/CEO, of Accuray told Medical Device Daily. “But the key difference for CyberKnife is that its precision is much higher and we can avoid delivering radiation to critical parts of the lung. If a tumor isn't centrally located in the lung we believe that CyberKnife is the only true solution.“

Because fiducial implantation is no longer required, CyberKnife radiosurgery with Lung Optimized Treatment offers a completely non-invasive option, which is particularly important for medically or surgically inoperable patients. This means patients who are not candidates for fiducial placement or physicians who choose not to implant fiducials due to the high risk of pneumothorax, now have a non-invasive alternative using the CyberKnife system's unique tracking and correction capabilities.

“Sometimes doctors would need to place small metal markers on the tumor, so even though the surgery was minimally invasive, the act of placing these markers on the tumors required an incision,“ Thomson said. “The purpose of our latest indication is to eliminate the markers being placed.“

“With the FDA 510(k) clearance of Lung Optimized Treatment, we've taken the CyberKnife technology to new heights and enabled care for an expanded group of patients,“ Thomson added “This is yet another step in our efforts to ensure physicians have access to the treatment choices necessary for their patient, based on the patient's specific needs. To this end, Accuray continues to investigate ways to improve patient care across various indications.“

CyberKnife was created in 1991 and received FDA approval for in-the-body use in 2001.

To date, the device has been used on more than 100,000 patients with 25% of those being treated in the “previous 12 months,“ according to Thomson. It has also been featured in numerous studies on different parts of the body.

A little more than a year ago, the company received positive marks for the device in a prospective clinical study that shows the application has the ability to treat prostate cancer in patients at a much faster rate than other previous applications (Medical Device Daily, April 7, 2009).

The study, which was started in 2003 and led by Christopher King, MD, at the Stanford University School of Medicine (Stanford, California), treated 41 low-risk prostate cancer patients using CyberKnife radiosurgery. Continual image guidance was used to verify target position throughout the procedure allowing the team to precisely deliver very high doses of radiation in five short treatments.

At a median follow-up of 33 months, no patient experienced a PSA recurrence and early side effects were no worse than other prostate cancer therapies.

The authors referred to the findings as “highly encouraging,“ but they said that longer follow-up is required “to confirm durable biochemical control rates and low late toxicity profiles.“

Thomson said that researchers are now investigating how the application can more accurately treat breast cancer and noted that there were two key studies on this subject.

These two studies, from the University of Texas Southwestern (Dallas) and Fox Chase Cancer Center (Philadelphia), were presented at the 52nd annual meeting of the American Society for Radiation Oncology (Fairfax Virginia) in San Diego from Oct. 31 to Nov. 4.

Surgeons used the device in a technique called partial breast irradiation, which can be as effective as whole breast irradiation and is less likely to cause damage to the heart, lungs, and skin, leading to improved cosmetic outcomes and reduced toxicities.

The treatment regimen using the CyberKnife system would be five days compared to 25-30 days typically associated with conventional radiation therapy.

Thomson said that the firm isn't looking to develop the next generation of the device but rather to improve and streamline the effectiveness of the current iteration of CyberKnife.

“Our current strategy is to develop and fine tune CyberKnife,“ Thomson said. “It's our intent to maximize improvements and upgrades for the device.“

Omar Ford;404-262-5546;