CyberKnife in the treatment of prostate cancer: a revolutionary system

The CyberKnife is a frameless advanced robotic system that uses image-guided radiotherapy (IGRT) and adaptive radiotherapy (ART) for stereotactic radiosurgery technique in intra- and extracranial lesions. This system represents, after three-dimensional conformal radiotherapy (3DCRT), a new frontier in the treatment of prostate cancer, applying the same dosimetric and biologic considerations as with high-dose-rate (HDR) brachytherapy There is our experience with six assessable patients. To better understand our experience we have treated 3 patients and we have implanted 3 more patients who are currently undergoing treatment. The average age was 74.8 yr of age (patients of >70 yr of age were deliberately chosen for the study), with an average International Prostate Symptom Score (IPSS) of 15.1 and average five-item International Index of Erectile Function (IIEF-5) score of 23. The scheme used was four hypofractions of 9.5 Gy, for a total of 38 Gy. The average PSA 6 mo after treatment was 0.8 ng/ml and had fallen in all the patients. The IPSS after about 2.5 mo had returned to normal, while the score for erectile function remained almost unchanged. The future of this frameless robotic radiosurgery system may, indeed, be to use it not only as monotherapy but also in conjunction with other boosters after radiotherapy.