CyberKnife Therapy for Head and Neck Cancers
Frequently Asked Questions
» What is CyberKnife and how can it be used to treat head and neck tumors?
» When was CyberKnife approved to treat head and neck tumors?
» What are CyberKnife's advantages for head and neck tumor treatment?
» How effective is CyberKnife in the treatment of head and neck tumors?
» What is the process involved in receiving CyberKnife therapy for head and neck tumors?
» What side effects may be associated with CyberKnife head and neck tumor treatment?
Q. What is CyberKnife and how can it be used to treat head and neck tumors?
CyberKnife is a robotically controlled radiation delivery machine. It was originally developed primarily as a device to deliver Stereotactic Radiosurgery (SRS) for tumors of the brain and has been used for more than three decades to treat brain tumors. It is now approved to treat tumors anywhere in the body, including the head and neck.
SRS is a radiation treatment technique in which high doses of radiation are delivered using a very precise beam (or beams) during a single treatment session. With this technique, up to 200 separate beams are focused on the tumor. The beams are very narrow so that a very high amount of radiation can be delivered to a very small area. The aim is to use such a high dose that the tumor is destroyed. The delivery has to be performed with great precision.
Older types of radiation therapy required head and neck cancer patients to have their heads locked in place using tight holding devices or frames sometimes screwed into their skulls, so that the beams of radiation could be properly targeted to the tumor. CyberKnife takes standard X-ray images during the treatment without need of the head-holding frame. The radiation coming from the CyberKnife machine is the same type used in standard external beam radiation machines.
Q. When was CyberKnife approved to treat head and neck tumors?
CyberKnife was cleared by the FDA in 1999 to treat tumors in the head, neck, upper spine and base of the skull. In 2001, it was approved to treat tumors in any part of the body.
Q. What are CyberKnife’s advantages for head and neck tumor treatment?
Because CyberKnife involves no cutting, it offers patients a non-invasive alternative to head and neck cancer surgery and can be used for tumors that are considered inoperable because of their location, or for those patients who cannot undergo surgery because of their poor medical condition or who refuse surgery.
Head and neck cancers develop when abnormal cells develop and grow in areas including the mouth, nose and throat. They can also grow in the oral cavity, including the lips, cheeks and tongue; salivary glands; pharynx; trachea; larynx; and lymph nodes in the upper part of the face.
Conventional radiation is a common treatment for head and neck cancers. A challenge is that conventional radiation can be used only once. Using it again at the same dose causes harmful complications, while at lower doses it is not effective. In some cases, CyberKnife can be used to treat head and neck cancers even after conventional radiation. It uses computers and imaging tools to pinpoint the exact location of the tumor and uses the Synchrony Respiratory Tracking System to track movement of the tumor even when a patient is breathing. Unlike other systems, CyberKnife does not require patients to be fitted with a rigid and invasive head frame.
CyberKnife head and neck cancer treatments are typically performed on an outpatient basis over a period of up to five days and require no overnight stays. Most patients experience minimal to no side effects with a quick recovery time.
Q. How effective is CyberKnife in the treatment of head and neck tumors?
A 2012 Chinese study published in Experimental and Therapeutic Medicine looked at CyberKnife treatment of 160 high-risk patients, including 55 with head and neck tumors. It concluded that CyberKnife is undoubtedly a safer treatment modality for high-risk or highly difficult cases. One patient in the study, who had lung cancer with mediastinal lymph node metastases (15 lesions), was a highly difficulty case. After treatment using CyberKnife, the tumor lesions completely disappeared. After the applied research of CyberKnife in 160 advanced high-risk (or difficult) tumor cases, the Chinese researchers believed that CyberKnife cannot only quickly improve the clinical symptoms of patients and obtain satisfactory short-term curative effects, but is also suitable for the treatment of high-risk tumors, thus curing the incurable tumors.
A 2011 Japanese study reported preliminary data on 34 patients given CyberKnife treatment for primary tumors, including 21 who had previously failed conventional radiation treatments. They concluded that CyberKnife is effective for head and neck tumors and has the advantage of short treatment duration. However, they warned of potential dangers associated with re-irradiation following conventional treatment and said special caution is warranted. Overall survival was better in those who had not had previous radiation treatment. They said: “We believe SBRT for head and neck tumors will evolve as a result of more extensive experience and thus merits further study.”
A 2009 study done at the University of Pittsburgh and published in the International Journal of Radiation Oncology looked at CyberKnife treatment of 21 patients who had previously been irradiated for squamous cell head and neck tumors. They found the treatment was feasible and well tolerated.
A 2003 Japanese study published in the Japanese Society for Therapeutic Radiology and Oncology looked at 31 patients who had previously been irradiated and then underwent CyberKnife treatment. It concluded that “our experience shows that CyberKnife is expected to be a feasible treatment for previously treated recurrent head and neck cancer and for the reduction of adverse effects and maintenance of a useful quality of life.”
Q. What is the process involved in receiving CyberKnife therapy for head and neck tumors?
Patients are treated by a team, which includes a neurosurgeon, an otolaryngologist, a radiation oncologist, a radiation therapist, and other support personnel. The process involves setup and imaging, treatment planning, and CyberKnife treatment. Before treatment begins, the brain is imaged by CT, MRI or PET scan to precisely determine the location of the tumor. The team determines the location, size and dosage needed and identifies areas of nearby healthy tissue that must be spared radiation.
The patient wears a plastic mesh mask during the imaging process to help keep still. The mask is also worn during treatments. The data is used to design a custom treatment plan. Treatment may occur over the course of several days. At the outset of treatment, the system’s computer controlled robot moves around the body to the various locations from which it will deliver the radiation.
Q. What side effects may be associated with CyberKnife head and neck tumor treatment?
Most side effects are minimal and disappear quickly. Patients are also told that their tumors will not suddenly disappear and that it may take months to determine the effectiveness of the treatment.