CyberKnife delivers high dose brachytherapy for prostate cancer non-invasively
18 April 2008
The CyberKnife robotic radiosurgery system can serve as a non-invasive means for delivering high dose rate (HDR) brachytherapy dosing, according to a study published in the International Journal of Radiation Oncology* Biology* Physics.
The study supports the system's clinical flexibility in treating prostate cancer and expands the non-invasive options available to clinicians and patients.
HDR brachytherapy has been shown to be an extremely effective approach for treating prostate cancer, with substantial clinical evidence supporting its usage. Nevertheless, the required insertion of multiple catheters into the prostate, where they remain for the duration of the procedure (typically 1-3 days), makes it an invasive procedure.
This study demonstrates the CyberKnife System's ability to non-invasively deliver complex HDR-like radiation dose sculpting to the prostate, without the need for hospitalisation or anaesthesia, maximizing patient comfort and convenience. Early clinical outcomes of the study show a rapid reduction in prostate specific antigen (PSA) levels with minimal short-term side effects.
"HDR brachytherapy is an effective, accepted treatment for prostate cancer, but adoption has been limited because it is a difficult procedure for clinicians to deliver and for patients to undergo," said Donald Fuller, MD, radiation oncologist, CyberKnife Centers of San Diego and Radiation Medical Group, and principal investigator in the study. "Our study concluded that CyberKnife radiosurgery can offer the benefits of HDR brachytherapy non-invasively on an outpatient basis that is both easy to deliver and comfortable for patients."
This study, titled 'Virtual HDR(sm) CyberKnife Radiosurgery for Localized Prostatic Carcinoma: Dosimetry Comparison with HDR Brachytherapy and Preliminary Clinical Observations' supports the system's clinical flexibility and demonstrates its capability to create either a uniform distribution of radiation across the prostate or a pattern of dose that is similar to HDR brachytherapy.
The System's ability to track the location of the prostate, detect its position and correct the treatment beam angle continually throughout treatment ensures that either type of plan can be delivered accurately, accounting for the motion of the prostate during the treatment. The CyberKnife System gives clinicians a variety of non-invasive treatment delivery options, allowing them to customize the treatment to each patient's specific case.
"We are pleased to have published support of the CyberKnife System's diverse capabilities in prostate cancer planning and look forward to further clinical evidence following the publication of long term follow-up studies," said Eric Lindquist, senior vice president and chief marketing officer of Accuray, the manufacturer of CyberKnife.
Explanation of HDR Brachytherapy
HDR brachytherapy is a procedure commonly used in the treatment of prostate cancer. The procedure involves the insertion of catheters into the prostate gland, and then the delivery of a series of radiation treatments through these catheters.
A computer-controlled machine forces a seed containing a high energy radioactive source into the catheters one at a time, and then controls how long this seed remains in each of the catheters. This method allows different regions of the prostate to receive different doses of radiation (ie regions of the prostate expected to have large numbers of tumour cells receive higher doses of radiation than other parts of the prostate that may have a smaller amount of tumour cells).