Prostate Cancer Treatment
One of the challenges of treating cancer of the walnut-sized prostate gland is that the prostate’s position changes with the movement of other organs in the body. *
The CyberKnife® Robotic Radiosurgery System is able to continuously identify the exact location of the prostate tumor throughout the course of the treatment. During CyberKnife treatment, a patient can lie still and breathe normally while the physician zeroes in on the moving target – the prostate – and irradiates it without harming surrounding areas. As a result, the procedure is more comfortable for patients, radiation is delivered more accurately and treatments can be completed in one to five visits.
Currently, the CyberKnife Radiosurgery System is most frequently used as a single therapy for patients with early-stage prostate cancer confined to the prostate, or in combination with another therapy – such as external beam radiation – for patients with disease that extends beyond the prostate.
In presentations at scientific meetings and peer-reviewed publications, CyberKnife researchers have reported reliable reductions in PSA levels with low rates of mild side effects during short-term follow-up after CyberKnife monotherapy.
Depending on the stage of prostate cancer diagnosed, the physician will recommend a treatment plan.
Before a typical CyberKnife treatment
Prostate cancer treatment with the CyberKnife System involves a team approach.The team of specialists may include:
Medical support staff
Once the team is in place, preparations begin for CyberKnife treatment. As part of their diagnosis process, physicians will have measured prostate-specific antigen (PSA) levels via a blood test that will be used to help track treatment results.
Prior to CyberKnife treatment, the patient is scheduled for a short outpatient procedure in which three to five tiny gold “seeds” – fiducial markers – are inserted into the prostate. The fiducials are placed through a needle, which is guided via an ultrasound. The patient may be asked to clean out his rectum with an enema on the day of the fiducial placement.
The CyberKnife System uses the fiducials as reference points to identify the exact location of the prostate. Physicians will wait approximately one week after insertion of the fiducials before beginning CyberKnife treatment planning to ensure that fiducial movement has stabilized. A treatment plan is specifically designed by a medical physicist in conjunction with the patient’s physicians. The patient need not be present. During treatment planning, CT and/or MRI data is downloaded into the CyberKnife System’s treatment planning software. The medical team determines the size of the area being targeted by radiation and the radiation dose, and identifies critical structures – such as the bladder and rectum – where radiation should be minimized.
At this time, the CyberKnife System calculates the optimal radiation delivery plan to treat the prostate. Each patient’s unique treatment plan takes full advantage of the CyberKnife System’s extreme maneuverability, allowing for a safe and accurate prostate cancer treatment. After the treatment plan is developed, the patient returns to the CyberKnife center for treatment, which is usually delivered in one to five sessions.
The treatment session
For most patients, the CyberKnife treatment is a completely pain-free experience. They may dress comfortably in street clothes, and are free to bring music to listen to during the treatment. Patients also may want to bring something to read or listen to during any waiting time, and have a friend or family member accompany them to provide support before and after treatment.
At treatment time, the patient lies on his custom body cradle. The radiation therapist ensures that the body cradle is properly adjusted and the patient is appropriately positioned on the treatment couch. When the patient is ready for treatment to begin, the location of the prostate is tracked and detected. The medical team monitors every step via closed-circuit TV as the CyberKnife tracks the patient’s prostate, safely and precisely delivering radiation to the prostate tumor.
The CyberKnife System’s computer-controlled robot moves around the patient’s body to various locations from which it delivers radiation. At each position, the robot stops and special software determines precisely where the radiation should be delivered. Nothing is required of the patient during the treatment, except to relax and lie as still as possible.
Once prostate cancer treatment is complete, most patients quickly return to their daily routines with little interruption of their normal activities. If treatment is being delivered in stages, the patient will need to return for additional treatments over the next several days as determined by his physicians.
To date, prostate cancer patients have experienced only minimal short-term side effects from CyberKnife treatments. Data is still being collected to evaluate long-term toxicity. Occasionally, patients report temporary symptoms, which may include reduced urinary stream, burning with urination, more frequent urination, increase in frequency of stools, loose stools and more gas with bowel movements than usual. Physicians will discuss all possible side effects with their patients prior to treatment. In addition, they may prescribe medication to control any side effects, should they occur.
After completing a CyberKnife radiosurgery treatment, it is important for patients to schedule and attend any follow-up appointments. Response to prostate cancer treatment varies from patient to patient. Clinical experience today examining treatment outcomes up to three years following treatment has shown that most patients respond very well to CyberKnife treatments. Physicians will monitor the outcome in the months and years following a patient’s treatment using PSA tests and digital rectal exams.
*Source material drawn from www.cyberknife.com. Please refer to that website for a complete listing of references used in the original information sections.
CyberKnife® is a registered trademark of Accuray Incorporated.