Most advances in cancer treatment are small steps forward, but occasionally there is a giant leap. The CyberKnife® System is a robotic radiosurgery machine that is revolutionising the way cancers are treated. It was developed by John Adler, a neurosurgeon from Stanford University in the 1990’s as a way of extending radiosurgery from the head to include the rest of the body. He went on to found Accuray Incorporated, manufacturers of the CyberKnife® System. CyberKnife® is in clinical use throughout the world with over 60,000 patient treatments conducted.
What is CyberKnife®?
Conventional radiotherapy uses large field sizes and just a few radiation beams to treat ‘regions’ in the body which means the dose given to the tumour is often limited by the radiation tolerance of surrounding normal tissues. The CyberKnife® system is completely different as it uses hundreds of pencil thin beams and thousands of potential treatment angles to target individual tumours. The machine consists of a highly manoeuvrable miniaturised linear accelerator (a machine that delivers high energy x-rays) attached to a robotic arm. Bavarian Motor Works (BMW) originally created this robotic arm for manufacturing their cars. This robotic arm is complimented by a state-of-the-art targeting system which pinpoints tumours with sub-millimetre accuracy and then fires in hundreds of high dose pencil-thin beams of radiation.
Cyberknife explanation
What makes CyberKnife® so special?
It is a very accurate form of radiation treatment that can be used as an alternative to surgery in many cases. The key is delivering the right dose to the right place at the right time whilst minimising damaging effects on normal tissue. I like to think of it as “precision without incision”. Technology advancements enable the use of highly innovative and sophisticated planning and targeting software to treat tumours, even moving up and down to track the target as the patient breathes, minimising any radiation dose to normal tissues. Theoretically any tumour target can be cured with radiation therapy, historically this has been limited by the tolerance of surrounding normal tissue; CyberKnife® has changed this concept overnight with obliterative doses of radiation delivered rapidly and with absolute precision. In radiotherapists’ terminology it combines extreme hypo fractionation (where radiation is given in larger doses or ‘fractions’ and in less sessions than traditional radiation therapy) with intrafraction Image Guided Radiotherapy (IGRT) and extreme Intensity Modulated Radiotherapy (IMRT) to produce a near-perfect dose distribution of radiation around the target, with minimal dose to surrounding healthy tissue. This enables the very high doses used to be given with absolute safety and confidence.
Accuray promotional video
What can CyberKnife® treat?
Patients who were previously untreatable may now have hope. The CyberKnife® System can treat tumours all over the body and not just the brain as per some older machines. What makes it unique is that it can be used as an alternative to invasive conventional surgery in many cases.
Major operations such as lung and liver resections, removal of pancreas and prostatectomy now have a viable alternative option with this technique.
CK vs other options
Tumours in the body
Current indications include the treatment of stage 1 or 2 non-small cell lung cancer, lung metastases, spinal tumours, locally advanced pancreatic tumours, early prostate cancer, and treatment of primary or secondary liver tumours. This technology can also be used to retreat cancers that have recurred following conventional radiotherapy, for example head and neck or rectal cancers. These are situations that were previously untreatable using radiation.
Cyberknife Lung explained
CK Lung patient video san diego
CK Intracranial patient video
CK Prostate patient video san diego
CK liver & pancreas patient video san diego
Tumours in the brain and spine
Within the brain CyberKnife® can be used for the same indications as Gamma Knife including brain metastases, pituitary tumours, acoustic neuromas, meningiomas, AV malformations and trigeminal neuralgia. The use of 6-dimensional skull tracking makes this treatment at least as accurate as gamma knife without the inconvenience of a frame bolted to the patient’s skull. With the opening of the cancer centre, The London Clinic will have an essential tool for patients with limited disease as Cyberknife® is not usually appropriate for patients with widespread metastases.
CyberKnife Brain tumours explained part 1
CyberKnife Brain tumours explained part 2
CK Spine patient video san diego
What happens before treatment?
Patients will have a CT planning scan in order for the clinical oncologist, radiologist and physicist to determine the correct treatment volume, organs at risk, and radiation dose distribution. This scan can be fused with other imaging modalities such as MRI, PET scans and 3D angiography. Some tumours require the implantation of metallic markers, the size of a grain of rice (called fiducial markers), which help the software track the tumour more accurately. This can usually be done under local anaesthetic, one week before treatment. The treatment is explained in detail to each patient at a dedicated consultation, where discussions of any possible side effects will also take place. Due to the accuracy of targeting there have been very few serious side effects.
CK Treatment planning video
How long do treatment sessions last?
Treatments can last about an hour, are completely painless and usually non invasive. Most patients will have up to five treatments in contrast to conventional radiotherapy which involves up to 40 treatments, although there is now increasing use of single fractions with CyberKnife®.
Does it work?
CyberKnife® is a new technology, so there is currently a lack of large randomised clinical trials. The published data so far suggests that CyberKnife® is at least as effective as other forms of treatment in many indications, and very safe.
Who will provide my care?
All patients being considered for CyberKnife® will have their care planned with a multidisciplinary team made up of specialised clinical oncologists, surgeons, radiographers and radiologists. The CyberKnife® consultation itself is provided by one of the dedicated clinical oncologists, who will also supervise all aspects of the treatment.
What training was necessary?
The treating team were trained by Accuray and have spent time observing and then supervising and delivering treatment on other CyberKnife® machines in the UK and abroad. They have also attended conferences and symposia to obtain the very latest treatment data. The Clinical Oncologists have to complete additional training as CyberKnife® planning and treatment delivery is so different to conventional radiotherapy.
How do I refer patients for CyberKnife®?
The London Clinic CyberKnife® will be the second in the UK after the Harley Street London CyberKnife Centre opened in March 2009. Treatments can take a few months to set up with insurers, and NHS ETA applications are also a lengthy process, so referrals need to come through as soon as possible after CyberKnife® is discussed as a possible treatment option. Referrals are expected from a wide range of specialist surgeons and oncologists as well as directly from patients as the CyberKnife® is so versatile. Referrals can be made through the CyberKnife® centres or by contacting Andrew Gaya directly.
The future
The potential of this machine is incredible, and the next few years will see some exciting developments in cancer treatment. Phase 3 trials are now underway including a study of CyberKnife® against conventional surgery for stage 1 or 2 lung cancer. CyberKnife® is being tested in functional brain disorders such as epilepsy and Parkinsons disease, and there are plans to extend it to correct electrical disturbances in the heart (alternative to catheter ablation). Continual software improvements and upgrades to the CyberKnife® System mean that as each year passes, fewer tumours require metallic markers to be inserted and that eventually CyberKnife® may be 100% non-invasive. CyberKnife® is currently the pinnacle of radiation treatment delivery and I am proud to have this world class technology available to use on my patients.
Patrick Swayze documentary