Locally Recurrent Disease
Prostate cancer that locally recurs following radiotherapy provides a particularly vexing management problem. Radical prostatectomy has been performed in these patients with some success( 30, 31), but the difficulty of radical prostatectomy in this scenario is formidable, due to tissue changes created by radiation. Briefly, these include scar tissue surrounding the prostate, and obliteration of small peri-prostatic blood vessels over time, reducing the ability of surgically treated tissue to heal.

Permanent source brachytherapy (seed implant) has been performed in this setting, with some success, though the experience is small and inconsistent, and serious complications are possible (32). Cryosurgery (prostate freezing) has also been applied in this setting with roughly comparable results to brachytherapy (33). There is little if any precedent for attempting additional external beam radiotherapy, due to the elevated potential for catastrophic radiation-induced tissue damage.

In summary, there is no easy solution for patients who fail locally following external beam radiotherapy, who often receive palliative androgen suppressive therapy (hormone therapy) instead of further potentially curative therapy as a result.

CyberKnife® radiosurgery represents a potentially effective and safer treatment alternative for these patients, due to its “surgical” radiation dose sculpting and target tracking capability, though this approach has not been specifically investigated as of the date of this writing. Ideally, CyberKnife® salvage of post-radiotherapy local recurrence would be done under the direction of a clinical trial, though in the interim, this may also be considered outside of a clinical trial setting, in a patient who is fully informed as to the procedure, alternatives and CyberKnife® procedural risks.