Cyberknife Treatment Options

Cyberknife treatment, with the support of WorldMed Assist, is accessible at high caliber hospitals in the US and abroad. We generally choose medical facilities certified by JCAHO or the Joint Commission International (JCI) for partnerships. In addition, the international hospitals work in co-operation with medical facilities in the US, such as Johns Hopkins and Harvard Medical, to achieve excellence in medical care. Our medically educated case managers are trained to facilitate your treatment with a personal approach appropriate for your specific circumstances.

Advanced state-of-the-art Cyberknife Equipment

Most importantly, we provide you with a personal touch from start until well after your return home.

Options for quality Cyberknife Treatment include:

• Cyberknife Treatment in the U.S.
• Cyberknife Treatment in Turkey
• Cyberknife Treatment in India

We also provide information on costs:

• Cost of Cyberknife Treatment

What is Cyberknife cancer treatment?

Cyberknife is a non-invasive frameless stereotactic radiosurgery system that treats tumors anywhere in the body. Cyberknife is the robotic system that utilizes the skeletal structure of the body as a reference, eliminating the need for the invasive frame for intracranial lesions. It can be applied to the whole body including the targets in medulla spinallis and spine using one or multiple fraction. For a video explaining Cyberknife as an alternative cancer treatment, please see: cyberknife cancer treatment.

General patient characteristics

Three basic characteristics are important for patient selection in Cyberknife®
similar to other radiosurgery applications. Firstly, patients should have reasonable overall survival after radiosurgery treatment. Benign lesions are in this group and are easily treated with radiosurgery. Patients who have malign tumors and expected life is more than 6 months could be treated with radiosurgery. Secondly, capacity of patient cooperation to all diagnostic and treatment stages is important. Treatment time takes longer for patients who do not have complete cooperation. At last, patients whose tumor borders are clearly verified with radiological scans are good candidates for radiosurgery treatment.

Cyberknife target field size

Target field size is one of the important parameter for Cyberknife®
as in all other radiosurgery implementations. Acceptable lesion diameter is around 3 cm for intracranial lesions. Also, some institutes expand this until 3.5 cm.

Treating larger field sizes for some lesions can be possible with some of the features of Cyberknife®. We believe that especially for irregularly-shaped lesions, a non-isocentric plan can generate greater conformality than an isocentric plan. More homogenous dose distribution can be achieved while sparing the organ at risk. However clinical judgement should be exercised with all treatment plans. In addition, Cyberknife®
eliminates the need for the frame used in traditional radiosurgery system. Because of that irregular-shaped lesions around 4.5-5 cm diameter can be treated with Cyberknife®
using one or multiple fractions.

Proximity of critical structures

Lesion proximity to the critical structures is an important criteria for radiosurgery treatments. Some of the examples for critical structures are optic/vestibular/cochlear nerves and brainstem. Adjacent critical structures to the tumor can be treated with extreme precision and accuracy in Cyberknife therapy.
system. The manipulator enables unlimited beam positions, which provides access to many tumors that are unreachable by other radiosurgery systems. System can continuously track, detect and correct tumor and patient movement throughout the treatment.

Possibility of staged radiosurgery

It is very difficult to deliver high doses at once for some cases, especially for big
tumor size (around 4-5 cm diameter) and tumors near the critical structure. Total dose can be divided into multiple fractions and complication risk can be reduced with Cyberknife®
radiosurgery system.

Treatment indications

Acoustic neuromas

Radiosurgery is one of the agreed treatment modality for acoustic neuroma as well as surgery. Surgery is an inevitable technique on tumors with big diameter and pressing on brainstem. However radiosurgery in addition to surgery is commonly used in all over the world for acoustic neuromas with up to 3-3.5 cm diameter. Also complication risk can be reduced by increasing fraction number. *61 patient treated with Cyberknife®
in 1999-2001 were followed up for a minimum 36 months at Stanford University and 98% of treated tumor (60/61) were controlled (48% of 61 decreased in size and 50% of 61 were stable), only one treated tumor (2%) progressed after radiosurgery. Before treatment 13 patients had no hearing (Gardner-Robertson Gr V). Except of this group, all patients hearing level were preserved. Two of the patients hearing functions were better than before treatment (patient 1: from GR Gr:II to Gr:1 and patient 2: GR Gr:III to Gr:1). In no patients did new trigeminal disfunction develop, nor did any patient experience permanent injury to their facial nerve. Two patients experienced transient facial twitching after one year that resolved in 3 to 5 months. Cyberknife®
is a new radiosurgery technique that offer staged radiosurgery, higher conformality and low complication risk for acoustic neuromas.

Metastatic tumors

Of all brain metastases 30-60% originates from primary lung cancer, 10-30% from breast cancer and 5-21% from malign melanoma. Metastatic brain tumors are generally well-shaped and round lesions. They affect the surrounding tissues with pressing rather than infiltration. Surrounding infiltration field to the target is not larger than 5 mm for most cases. In cases with single brain metastasis, total excision and then whole brain irradiation (TBI) is the preferred treatment technique. However, in multiple and depth located brain metastasis, radiosurgery has been an efficient treatment modality for many years. Overall survival of patients can be increased without decreasing the quality of life by using single or combined techniques as mentioned above.

RTOG (Radiation Therapy Oncology Group) showed that mean survival time is 9.6 months for C1 group patients for multiple brain metastases with a single TBI treatment. Mean survival time was 11.6 months for the same group of patients when first TBI and then radiosurgery was applied. It increased to 15.2 months when first radiosurgery and then TBI applied. Cyberknife®
robotic radiosurgery reaches the same high tumor control ratios compared to other radiosurgery techniques and it also has higher conformality ratios on metastasis localized in critical regions.

Meningiomas

The most effective treatment is of course total surgical excision. Cyberknife®
presents a new alternative for residual tumors which are not totally excised due to their localization and for cases that can’t undergo surgery due to localization of tumor or patient’s situations. Cyberknife®
provides a high conformality using inverse-planning algorithm and non-isocentric beams for wide dural based and non-spherical lesions.

Arteriovenous malformations

As a result of rapid advancement in microsurgery technique, some studies with big patient number reported 90-99% cure rate in AVMs which have 3-4% annual bleeding risk and 1% mortality risk. Morbidity and mortality risks are changing between 8-18% and 1-5% respectively in surgical examination. Although surgical intervention displays successful results, radiosurgery is still an important therapy choice for small or middle AVMs localized deeply or in critical brain areas or unreachable. The mechanism of obliteration in AVM with radiosurgery is to cause hyperplasia in vascular intima giving rise to progressive shrival and obliteration. The development of this obliteration takes 3 years.

Pituitary adenomas

The primary therapy for pituitary adenomas is surgery. 8-15% recurrence and 0.3-1.8% mortality ratio are reported in different studies for pituitary micro adenomas with transsphenoidal surgery. Hormone control ratios are changing between 42 to 86% according to the type of hormone in hormone releasing adenomas. Although the radiosurgery series are small, some authors reported interesting results such as between 0 to 2% recurrence and 48 to 100% hormonal control ratios. The results of radiosurgery are generally satisfying in prolactinoma, acromegaly and Cushing adenomas. Nelson Syndrome results are not well enough with radiosurgery. Finally, it is possible to reach high tumor control ratios with Cyberknife®
in adenomas which are grown up after surgery or can not be completely removed with surgery due to closeness to anterior vision region.

Boost treatment in malign gliomas

Glial tumors are the most common tumors in brain. 35% of all brain tumors are diagnosed as an anaplastic astrocytoma (AA) or glioblastome multiforme (GBM). Especially in GBMs, the mean survival time is 1 year after aggressive surgery combined with conventional radiotherapy. Since these tumors are invasive and their borders are not detected properly in radiological investigations, the success of radiosurgery is limited in any type of them. Radiosurgery after surgery and conventional radiotherapy increases survival time significantly in malign tumors with radiologically well-detected borders.

In a study conducted by Bloomington, Okayama and Stanford groups together reported that mean survival time with Cyberknife®
boost therapy after surgery and conventional radiotherapy was 15 months. In this collective study, it was interesting to observe that when Cyberknife®
was applied in a single session, the mean survival time was 9.6 months; it reached to 15 months in staged radiosurgery. But further studies are needed with larger series considering performance of patients’ before surgery and Cyberknife®, age and neurological deficits.

Spine radiosurgery

Conventional radiotherapy techniques and intensity-modulated radiotherapy (IMRT) are used in spinal tumors. It is very difficult to immobilize spinal region with conventional immobilization devices. Also radiosurgery with linear accelerator requires invasive rigid external spinal frame so this method is not used widespread.

The present radiosurgery methods are applied only to intracranial area, so they need a metal stereotactic frame around the head. Cyberknife®
stereotactic radiosurgery system that is used not only to treat intracranial area but also the whole body has 3 features different from the other systems:

1. Xsight Spine Tracking System could be used in spine tracking. Xsight reduces the need for surgical implantation of fiducials, in the delivery of spine radiosurgery treatments.

2. The Xsight system registers unique non-rigid and bony anatomy landmarks to track, detect and correct the movement of the spine in real-time throughout the treatment.

3. Non-isocentric technique can be used for spinal lesions to get high conformality in tumor and lower radiation doses in medulla spinalis.

Cyberknife
spinal treatment indications

1. Previously irradiated lesions 2. Recurrent surgical lesions 3. Unlikely to operate conditions 4. Patients not undergo any operation due to limited survival 5. Any medical situation to prevent surgery 6. Not to have evident spinal instability

Cyberknife
contraindications

1. Having evident spinal instability 2. Neurological deficit due to pressure of bone structures 3. Previous radiotherapy dose exceeding medulla spinalis tolerance dose