CyberKnife® FAQs

CyberKnife® for Prostate Cancer: FAQs and Expert Comparison

Choosing between radiation and surgery is a pivotal decision for any man diagnosed with prostate cancer. In New York City, patients often ask about CyberKnife® Robotic Radiosurgery as a non-invasive alternative. Below, Dr. David Samadi provides an expert breakdown of how this technology works, its limitations, and how it compares to the gold-standard robotic prostatectomy.

Q: How is CyberKnife® used to treat prostate cancer?

A: CyberKnife® delivers targeted, high-dose radiation directly to the prostate tumor over 1 to 5 sessions. This method, known as Stereotactic Body Radiation Therapy (SBRT), is generally recommended for men with low-to-moderate risk prostate cancer. Unlike traditional radiation, the CyberKnife® system uses a robotic arm to track the prostate’s movement in real-time, which helps minimize (though not eliminate) radiation exposure to the surrounding healthy tissue.

Q: What are the specific steps of the CyberKnife® treatment?

A:

1. PSA Baseline: A PSA test is conducted to establish a pre-treatment benchmark.
2. Fiducial Markers: Small gold seeds are inserted into the prostate via an ultrasound-guided needle to act as tracking points for the robot.
3. Imaging: CT and MRI scans are performed while the patient rests in a custom-molded cradle to map the tumor’s exact dimensions.
4. Planning: Medical physicists and doctors devise a radiation delivery map.
5. Treatment: The patient lies in the cradle while the computer-controlled robot moves around the body, administering radiation.
6. Follow-up: Patients return for lifelong PSA monitoring and digital rectal exams (DRE) to ensure the cancer remains suppressed.

Q: What are the advantages of CyberKnife® treatment?

A:

• Shorter Duration: Treatment is completed in about a week, compared to the 35+ days required for traditional external beam radiation.
• Non-Invasive: No incisions are made, and there is typically zero downtime.
• Sub-millimeter Accuracy: The robotic tracking reduces accidental radiation of the bladder and rectum compared to older radiation methods.

Q: What are the disadvantages and risks of CyberKnife®?

A: Radiation is essentially a “best guess” treatment. Because the prostate is still in the body, doctors must approximate the radiation dose based on biopsies and scans, which can be inaccurate. Research indicates that prostate cancer staging changes in up to 40% of men once the tissue is actually removed and examined in a lab.

Furthermore, men who choose CyberKnife® are left with a fluctuating PSA level. The tumor may take years to disappear or may simply stay in the body with “stalled” growth. This leads to a lifetime of “PSA anxiety” and rigorous follow-up schedules.

Q: How does CyberKnife® differ from Robotic Prostatectomy?

A: It is a common misconception that CyberKnife® is surgery—it is not. It is a form of radiation.

In contrast, a Robotic Prostatectomy performed by Dr. Samadi at our Manhattan surgical center involves the physical removal of the cancerous gland. This allows for:

• Definitive Staging: We learn the exact type and extent of the cancer.
• Undetectable PSA: With the tumor gone, the goal is a PSA level of zero.
• Preservation of Options: If cancer returns after surgery, radiation is still an option. However, if cancer returns after CyberKnife®, surgery becomes extremely difficult due to radiation-induced scarring.

Q: What are the side effects of CyberKnife®?

A: Short-term side effects include urinary urgency, burning during urination, and rectal irritation. Long-term risks are more significant:

• Sexual Dysfunction: Impotence or ED may develop up to 2 years after treatment.
• Bowel Impairment: Chronic rectal bleeding or stool incontinence.
• Secondary Cancers: A small but documented increase in the risk of developing bladder or rectal cancer due to radiation exposure.

Q: Is CyberKnife® right for me?

A: While CyberKnife® can be an effective secondary measure for recurring cancer or for patients who are not candidates for surgery, robotic prostatectomy surgery remains the most effective way to eliminate the tumor entirely and provide long-term peace of mind.

For a detailed evaluation of your treatment options in New York City, contact Dr. Samadi’s office at (212) 365-5000.