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(Click on the image to enlarge)
Chordomas are slow growing
neoplasms arising from the embryonic spinal column or “notochord”. They
commonly occur in the base of the skull and result in the cranial nerve deficits
such as double vision, facial weakness and difficulty swallowing. Skull base
chordomas are rarely amenable to complete surgical removal. Traditionally,
postoperative irradiation is delivered to doses of 6000-6500 cGy. This approach
controls chordoma only for several years. Escalation of conventional
radiotherapy dose is associated with serious central nervous system side
effects. Prior to the introduction of shaped-beam stereotactic radiotherapy,
the only method for safely increasing the dose for chordomas was by proton beam
treatment. This form of radiotherapy, however, is available in only two centers
in the United States. At UCLA, skull base chordomas can now be treated safely
to doses of 7000 cGy or more over 6-7 weeks of daily treatment.
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