Prostate Cancer
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The CyberKnife® Prostate Radiosurgery Solution
Early stage disease
Stereotactic radiosurgery, sometimes also referred to in the literature as stereotactic radiotherapy, is a new technique that shows great promise in the treatment of early stage prostate cancer (27).
Technical notes
Treatment with CyberKnife® radiosurgery comes from literally hundreds of different angles, giving the treatment planning computer extreme freedom to conform the radiation dose to the target volume, while more effectively avoiding normal tissue compared with conventional radiotherapy techniques.
Due to its unique tumor tracking capability, the CyberKnife® device has a published accuracy of one millimeter (28), with a much sharper dose fall off at the target volume margin, effectively rendering the high dose radiation margin more “scalpel-like,” allowing a far smaller normal tissue expansion around the prostate volume. This CyberKnife® radiation dose conforming capability and margin reduction causes much better sparing of adjacent rectum and bladder from the high dose volume, allowing a substantial radiobiologic dose escalation, giving tissue ablative potential within the prostate target volume, with a low risk of complications beyond it.
The tight dose conforming to the prostate also allows hypofractionated treatment (few large treatments instead of many small ones) similar to HDR brachytherapy.
Cyberknife Dosimetry images reprinted with permission from Accuray
Written by Donald B. Fuller, M.D. – Radiation Oncologist