Cyber Knife - The ultimate weapon for fighting cancer

A new weapon in Penrose Cancer Center’s arsenal targets cancer cells with greater accuracy and better outcomes than ever before.

The CyberKnife® Robotic Radiosurgery System attacks tumors with precisely focused, powerful beams of radiation, making it possible to treat inoperable or complex tumors with no incisions, anesthesia, pain, recovery time, or hospital stay, and minimal or no side effects or complications. Most patients can resume activities almost immediately after treatment.

Most importantly, treatment with the CyberKnife® is highly effective.

Attacking cancer from all directions

The CyberKnife® combines the mobility of robotic technology with superintelligent automation and continual imaging. It allows radiation oncologists Dr. Anuj V. Peddada and Dr. Alan T. Monroe to treat tumors at Penrose Cancer Center with high doses of radiation delivered with precision anywhere in the body.

Key components of the system are a robotic manipulator arm that holds a compact linear accelerator, a real-time image guidance system that continually tracks the target tumor and provides feedback, high-resolution image detectors, and low-energy x-ray sources. The heart of the system is CyberKnife’s highly sophisticated software.

Before treatment, the patient undergoes a high-resolution CT scan to determine the location of the tumor. The imaging information goes to the CyberKnife’s treatment planning station, where the treating physician identifies the tumor and surrounding vital structures and determines the best radiation dose, then creates a treatment plan. As part of the treatment plan, CyberKnife’s software automatically determines the number, duration, and angles of delivery of the radiation beams.

Treatment of the patient is a complex dance orchestrated by the system’s software.

The patient reclines comfortably on the treatment table, which automatically repositions during the procedure. The CyberKnife’s robot moves slowly around the patient, bombarding the tumor with hundreds of powerful radiation beams from many directions. Before the delivery of each beam, two ceiling-mounted x-ray components take images of the treatment area. The system compares the images with the original CT scan to track, detect, and correct for any movement of the patient or tumor.

The amount of radiation delivered during imaging is quite low compared with the powerful doses fired at the tumor, and because the delivery angle constantly changes, only a fraction of the high-dose radiation touches surrounding healthy tissue.

Treatment usually lasts 30 to 90 minutes; most patients require one to five treatments. Follow-up imaging usually is performed to confirm the destruction and eventual elimination of the tumor.

Advantages over conventional treatment

Conventional radiation therapy requires 30 to 45 treatments to deliver low doses of radiation and generally is used as an adjunct to surgery. The CyberKnife® system delivers high radiation doses in one to five treatments, and can be used as an alternative to surgery for appropriate patients.

“If you treat lung cancer with standard doses of radiation, you treat every day for six to seven weeks in 30 to 35 doses,” Dr. Monroe says. “It is very inconvenient and very costly, and even with the earliest Stage I tumors, you get a 20 to 30 percent cure rate. With the CyberKnife®, treatment is completed in three days.”

Expected control rates for the treatment of Stage I lung cancer with radiosurgery are 80 to 90 percent, rivaling those of surgical treatment.

One of the biggest enhancements of the CyberKnife® system is its ability to correct for movement of the patient or the tumor.

Lung tumors, for example, move constantly with radiation. Conventional radiation therapy requires irradiation of the entire area where the tumor might be, whereas the CyberKnife® continually pinpoints the tumor’s location.

“Techniques utilized by other systems require mechanical compression of the chest or abdomen to control breathing,” Dr. Peddada says. “The CyberKnife® system studies the patient’s breathing pattern and creates a model that adapts to their breathing. If the patient’s breathing changes or the patient coughs or sneezes, it will remodel the pattern.” The patient can relax during treatment and breathe normally.

Unlike some types of radiation therapy, the CyberKnife® system does not require immobilizing the head with a helmet or use of a body frame to deliver treatment to other areas of the body.

CyberKnife® applications

The CyberKnife® system can be used to treat cancers and other lesions throughout the body, including primary, metastatic, and recurring cancers of the head, neck, lungs, and liver, as well as other tumors throughout the body. It also is used to treat nonmalignant lesions and conditions such as meningioma, schwannoma, and trigeminal neuralgia.

Patients who are not eligible for surgical or other radiological treatment can be treated with CyberKnife, although CyberKnife® is not for everyone.

“Certain patients are better treated with surgery first,” Dr. Peddada says. “For example, if there is a large tumor pressing on other organs, we might first take out the bulk of the tumor. The surgeon can scale back the operation if, for example, the tumor is close to a nerve. The remainder of the tumor is treated with the CyberKnife.”

Treatment may be combined with other modalities such as traditional radiation or chemotherapy.

Even in patients with stage IV cancer, “we can use it to help relieve symptoms in particular areas, for example, metastatic lesions to the spine. Those can be treated with one treatment.”

Another advantage to patients is the lower cost of CyberKnife® treatment—about half that of traditional radiation therapy. For prostate cancer, for example, radiation therapy costs about $40,000; CyberKnife® treatment averages about $24,000.

The CyberKnife® was developed by John R. Adler, MD, professor of neurosurgery and radiation oncology at Stanford University Medical Center. Its robotic component was based on the robotic system designed in Germany to build the Mercedes Benz. The system was approved by the U.S. Food and Drug administration for treatment of tumors in the head and base of the skull in 1999, and cleared for use against tumors anywhere in the body in 2001. To date, more than 50,000 patients worldwide have been treated with CyberKnife®.