Spine Cancer:

A spinal tumor is a growth of cells
(mass) in or surrounding the spinal
Tumors that have spread to the spine
from another site (metastatic tumors)
often progress quickly. Primary tumors
often progress slowly over weeks to


Metastatic tumors in the spine and
bone are particularly treatable with
CyberKnife, as are osseous
metastases. This includes those that
are not suitable for surgical resection
and conventional radiotherapy.

How does CyberKnife spinal
radiosurgery work?
The CyberKnife enables the minimally
invasive and extremely accurate
delivery of aggressive doses of
radiation to many spinal lesions. At the
heart of this surgical instrument is a
miniature linear accelerator, for
producing high energy therapeutic x-
rays, attached to a robotic arm. While
the robot arm moves extensively
around a patient, x-ray beams are
precisely targeted to the tumor from
hundreds of different directions.

Perhaps of even greater significance,
the CyberKnife eliminates the need for
a rigid external frame to be attached to
the patient's skeleton. Instead, the
CyberKnife uses an x-ray (diagnostic
energy as opposed to therapeutic
radiation) image-guidance system that
identifies the real-time position of the
patient's bony anatomy and target
throughout treatment delivery.

The CyberKnife tracks the position of a
spinal tumor with reference to either
the skull anatomy (for tumors of the
upper neck), or with reference to small
stainless steel screws called fiducials.
These metallic markers are anchored
to the bones of either the lower neck,
mid or lower back, the cervical,
thoracic and lumbar spine,
respectively, in a short outpatient
procedure. Once in position, these
fiducials can be automatically detected
by the image-guidance system of the
CyberKnife and used to determine the
exact position of the tumor. This
capacity to accurately target a spinal
tumor without rigid external
immobilization makes the CyberKnife a
unique solution for non-invasively
treating many spinal lesions with

Which spinal tumors are treatable with
the CyberKnife?
The CyberKnife has the potential to
treat most types of spinal tumors.
However, if a lesion is to be considered
for CyberKnife radiosurgery, it must be
reasonably discrete (distinct from the
surrounding normal tissues) on CT or
MRI images, and it cannot be too large
in size--generally speaking, a volume
of 150 cc is the upper limit of what is
treatable. Both benign (non-
cancerous) and malignant (cancerous
or capable of spreading to other sites
in the body) spinal tumors can be
treated with the CyberKnife.

Benign Lesions:
•arteriovenous malformations
•other: giant cell tumor, aneurysmal
bone cyst, epidermoid

Malignant Tumors:
•spinal metastases from many sources
•Ewing sarcoma