Prostate Cancer CyberKnife Data

• Stereotactic Body Radiation Therapy for Prostate Cancer. H. Ishiyami. Stereotactic body radiation therapy (SBRT) is a promising treatment option for prostate cancer. Hypofractionation regimens, such as SBRT, may be more advantageous compared with conventional regimens because low α:β ratio of prostate cancer has high sensitivity to dose per fraction. In addition, a smaller and tighter margin with SBRT is expected to provide a low toxicity rate without reducing tumor control. The purpose of this article is to examine radiobiological, technical and clinical aspects of SBRT for prostate cancer.

• CyberKnife radiosurgery for prostate cancer. A. Katz. This review summarizes the motivating factors for the treatment of prostate cancer with CyberKnife SBRT. Also, presented is an evaluation of the current literature and discussion of the future of prostate cancer treatment with SBRT.
• Long-Term Outcomes from a Prospective Trial of Stereotactic Body Radiotherapy for Low-Risk Prostate Cancer. King et al. 2011. In this update to Stanford University’s Phase II clinical trial of 67 low-risk prostate cancer patients treated with the CyberKnife System, the four-year Kaplan-Meier PSA relapse-free rate was 94%. Urinary and rectal toxicities were infrequent and not severe, equal to or lower than those in dose-escalated 3D-CRT studies and hypofractionated IMRT studies.
• Stereotactic Body Radiotherapy as Monotherapy or Post-External Beam Radiotherapy Boost for Prostate Cancer: Technique, Early Toxicity, and PSA Response. Jabbari et al. 2010. University of California at San Francisco researchers present results on the first 38 patients treated with their CyberKnife System. They adopted a four-session treatment approach based on their successful experience with high dose-rate (HDR) brachytherapy—using the CyberKnife HDR-like dose distributions could be delivered non-invasively. At a median 18 months follow-up toxicity has been minimal and ”PSA response as defined by PSA nadir to date has been excellent.”
• Stereotactic body radiotherapy for low-risk prostate cancer: five-year outcomes. Freeman & King. (Paper available for free at this link). Researchers from Stanford University and Naples Florida present the first report of 5-year follow-up for CyberKnife treatment of prostate cancer. For their combined cohort of 41 low-risk prostate cancer patients, the 5-year disease-free survival rate is 92.7% with generally low rates of mild GU and GI toxicity.
• Stereotactic body radiotherapy for organ-confined prostate cancer. Katz et al. 2010. Winthrop University researchers used the CyberKnife System to treat 304 patients with clinically localized prostate cancer. For those patients with a minimum of 12 months follow-up, 98% overall biochemical control rate was obtained. Both acute and late toxicity were mild and erectile function was preserved in 87% of patients at 18 months.
• Acute toxicity after CyberKnife-delivered hypofractionated radiotherapy for treatment of prostate cancer. Townsend et al. 2010.# Researchers at Drexel University report on the treatment of 50 patients with early-to-intermediate, organ-confined prostate cancer using the CyberKnife System. Acute toxicity included 10% Grade 2 and 6% Grade 3 gastrourinary (GU) toxicities. No Grade 2 or higher acute gastrointestinal (GI) toxicities were reported. The authors state that "both GU and GI symptoms were comparable to or lower than those that have been reported for either IMRT or 3D-CRT and HDR brachytherapy".
• Stereotactic body radiotherapy as boost for organ-confined prostate cancer. Katz et al. 2010. (Paper available for free at this link). Researcher from Winthrop University report on the treatment of 41 intermediate- and 32 high-risk localized prostate cancer patients using the CyberKnife System as a boost to EBRT. Three-year actuarial biochemical control rates were 89.5% for intermediate-risk and 77.7% for high-risk patients.
• Image-guided stereotactic body radiation therapy for clinically localized prostate cancer: preliminary clinical results. Bolzicco et al. 2010 (Paper available for free at this link). In this study by researchers in Vicenza Italy, 45 low-intermediate risk patients were treated with 35 Gy in 5 fractions. At a median follow-up of 20 months no patient has recurred biochemically and toxicity rates have been low.
• Stereotactic body radiotherapy: an emerging treatment approach for localized prostate cancer. Friedland et al. 2009. Researchers from Naples, Florida presented their experience with prostate radiosurgery using the CyberKnife System. In these first 112 patients with early stage organ-confined disease, 97% biochemical control was obtained at a median of 24 months, with urethral/rectal toxicity comparable to EBRT. Erectile function was preserved in 81% of patients at two years.
• Virtual HDR CyberKnife treatment for localized prostatic carcinoma: dosimetry comparison with HDR brachytherapy and preliminary clinical observations. Fuller et al. 2008. Researchers from San Diego’s Radiosurgery Medial Group report that the CyberKnife System can achieve HDR-like dose distributions with excellent conformality and sharp dose fall off.
• Stereotactic body radiotherapy for localized prostate cancer: interim results of a prospective phase II clinical trial. King et al. 2008. Stanford University Researchers used the CyberKnife System to treat 41 low-risk prostate cancer patients. With a median follow-up of 33 months they found no patient had a PSA failure. They conclude that the early and late toxicity profile and PSA response for prostate treatment using the CyberKnife System are highly encouraging.