The CyberKnife System uses state-of-the-art robotics and advanced software, but it's not new. In fact, the system has over a decade of clinical evidence. The CyberKnife System is the only radiation therapy device supported by years of published clinical follow-up with a large number of patients. Two of these studies, the largest prospective multicenter studies to date, were conducted in community and academic hospitals across the United States, giving men peace of mind that excellent clinical outcomes can be achieved at any CyberKnife site. The CyberKnife System is helping thousands of men overcome prostate cancer and return to a healthy, fulfilling life faster.

The FDA granted approval to the CyberKnife System in 2001 for the treatment of tumors anywhere in the body, including the prostate. More than 20,000 prostate cancer patients have been treated to date with the CyberKnife System.³

Treatment with the CyberKnife System is a non-surgical, outpatient procedure that requires no incisions or general anesthesia. Most patients will not require hospitalization or a long recovery period.

The entire CyberKnife treatment for prostate cancer can be completed in as little as 4-5 sessions over 1-2 weeks, compared to conventional radiotherapy which typically requires 30-40 sessions over 8-10 weeks.

The most modern protocols have even developed single session protocols.

Treatment with the CyberKnife System is a non-invasive procedure and avoids the discomfort and risk associated with radioactive seed implants or catheters, local anesthesia, possible infection, hospitalization, and long recovery times.

Radiation therapy is a treatment that uses high-energy X-rays (photons) to kill, shrink, or control the growth of tumors. Radiation therapy works by damaging cells, preventing them from growing and dividing. The goal of any radiation treatment is to destroy cancer cells while minimizing side effects on healthy tissue. As imaging technologies have improved over the past few decades, radiation therapy has incorporated these improvements to optimize dose delivery and minimize side effects.

Radiation may be recommended as a primary treatment, as an alternative to surgery, or in addition to other therapies. There are several types of radiation therapy. The CyberKnife System delivers a type of radiation therapy known as stereotactic body radiation therapy (SBRT).

Stereotactic Body Radiation Therapy (SBRT) combines a high degree of localization accuracy with very high doses of extremely precise radiation delivered externally, thereby maximizing the cell-destroying effect on the tumor(s) while minimizing radiation-related injury to adjacent normal tissues.

SBRT treatment takes into account the interaction between prostate cancer cells and radiation. Studies have indicated that prostate cancer cells are highly sensitive to the amount of radiation delivered in each treatment session. This sensitivity suggests that a higher dose of radiation delivered in fewer sessions may result in better long-term disease control.⁴

Furthermore, compared to conventional radiotherapy which typically requires approximately 30-40 sessions over 8-10 weeks, prostate SBRT can be completed in 4-5 sessions over 1-2 weeks.

After a prostate cancer diagnosis, men face numerous treatment options, including active surveillance, radical prostatectomy, and radiation therapy. Each man should consult with his doctor regarding his specific case. Considerations a doctor will take into account when recommending treatment include the patient's overall health, age, lifestyle, and the particular aggressiveness of the cancer, often referred to as the "risk" profile.

The American Urological Association (AUA), the American Society for Radiation Oncology (ASTRO), and the Society of Urologic Oncology (SUO) endorse SBRT (such as the CyberKnife System) for certain cases of low- and intermediate-risk prostate cancer.5

Despite the higher dose rate associated with SBRT, multiple studies have validated that SBRT with CyberKnife is no worse than traditional radiation therapy.⁶ The ability to deliver precise radiation doses allows clinicians to decrease exposure to surrounding healthy tissue and minimize negative side effects on urinary, bowel, and sexual function that can reduce a patient's quality of life. Most patients can continue normal activities during and immediately after treatment. However, urinary incontinence, bowel problems, and erectile dysfunction are possible complications with any treatment option and should be discussed with your doctor.

CyberKnife treatment can be completed in as few as 4-5 sessions over 1-2 weeks, compared to conventional radiotherapy, which typically requires 30-40 sessions over 8-10 weeks. Each CyberKnife treatment session generally lasts 15-20 minutes, compared to conventional radiotherapy, which typically lasts 10-15 minutes per session.

CyberKnife System treatment is a non-surgical, outpatient procedure that does not require general anesthesia. Most patients will not require hospitalization or a lengthy recovery period. Most patients can resume normal activities during and immediately after treatment.

No anesthesia is required for CyberKnife treatment, and treatment sessions are completed on an outpatient basis. Some tumors may require the placement of fiducial stents within the prostate. This procedure would be performed under local anesthesia.

Most patients can resume normal activity during and immediately after CyberKnife treatment—compared to the typical requirement to limit normal activity for 4–6 weeks with traditional prostate cancer surgery. Importantly, patients treated with the CyberKnife System for prostate cancer reported a return to normal urinary and bowel function six months after the procedure.^7,8

Most patients can continue normal activity during and immediately after CyberKnife treatment — compared to the typical requirement to limit normal activity for three to five weeks with traditional prostate cancer surgery.

The robotic design, combined with real-time imaging, allows the CyberKnife System to deliver a maximum radiation dose directly to the tumor from virtually any angle with submillimeter precision throughout the treatment. The CyberKnife System achieves this by continuously tracking, automatically adapting, and synchronizing the radiation beam with the movement of the prostate or the patient in real time. This increased precision helps minimize the dose to surrounding healthy tissue, reducing the risk of many common side effects.^{9, 10, 11, 12}

The prostate gland can move unpredictably throughout the course of treatment, making the ability to track, detect, and correct this movement critically important. In fact, it has been documented that the prostate can move up to 5 mm in as little as 30 seconds due to normal bodily functions of the patient—such as bladder filling, bowel gas, or even slight patient movements during the procedure.^{13, 14}

This movement is particularly problematic because the prostate is surrounded by sensitive organs and tissues. Failure to synchronize the radiation dose delivery with the prostate's movement can result in a decreased dose delivered to the target—and an increased dose delivered to the surrounding healthy tissues. This can affect the overall effectiveness of the treatment and potentially increase the incidence and severity of side effects.

Unlike any other radiation treatment, the CyberKnife System continuously tracks, automatically adapts, and synchronizes treatment delivery with the prostate's movement in real time throughout the entire treatment session. This helps ensure that the radiation dose is delivered precisely to the target—maximizing treatment effectiveness while protecting surrounding tissues to reduce the incidence of side effects.

Precisely delivering the prescribed radiation dose to the target is essential for optimizing long-term cancer control. Furthermore, precise dose delivery reduces irradiation of healthy organs and tissues surrounding the target.

Because the prostate is surrounded by sensitive organs and tissues, precise administration is critically important — reducing the incidence and severity of side effects and protecting quality of life both during and after treatment.

SBRT is a form of hypofractionated radiation therapy. Compared to traditional radiation therapy treatments—commonly called conventional fractionation, which involves delivering a relatively lower dose of radiation, typically in 30–40 sessions over 8–10 weeks—hypofractionation involves delivering a higher dose per session (called a fraction) in a smaller total number of sessions. Hypofractionated treatment for prostate cancer can usually be completed in as few as 4–5 sessions over 1–2 weeks. Hypofractionated radiation therapy, such as prostate SBRT, has been shown to provide clinical outcomes as good as conventional fractionation—while dramatically reducing the number of treatments and the overall cost of care for both patients and payers.

Despite the higher dose rate associated with SBRT, multiple studies have validated that SBRT with CyberKnife is no worse than traditional radiation therapy.⁶ The ability to deliver precise radiation doses allows clinicians to decrease exposure to surrounding healthy organs and tissues and minimize negative side effects on urinary, bowel, and sexual function that can reduce a patient's quality of life. Most patients can continue normal activities during and immediately after treatment. However, urinary incontinence, bowel problems, and erectile dysfunction are possible complications with any treatment option and should be discussed with your doctor.

Extensive clinical research demonstrates that prostate SBRT with the CyberKnife System provides excellent long-term cancer control.

• Five years after CyberKnife SBRT of the prostate, disease-free survival (DFS) rates were:

• 97% – 100% for low-risk patients, superior to the 92% – 94% historical data for conventional radiotherapy15, 16, 17 and equivalent to low dose rate (LDR) brachytherapy18, 19 and high dose rate (HDR) brachytherapy13 without the discomfort and risk associated with invasive seed implants and catheters.

• 88% – 97% for intermediate-risk patients, equal to or greater than the 85% – 90% reported with conventional radiotherapy20, 21 without the inconvenience of daily visits for several weeks.

• Ten years after CyberKnife SBRT of the prostate, DFS rates were:

• 93% for low-risk patients, higher than the 81%–85%22,23 historical data for conventional radiotherapy and similar to HDR at 92%.13

Because the CyberKnife System's precise targeting significantly reduces irradiation of surrounding healthy tissue, patients treated with the CyberKnife System may be candidates for re-irradiation in the event of recurrence. Furthermore, patients treated with the CyberKnife System may occasionally be candidates for surgical intervention in the event of recurrence.

Because the CyberKnife System's precise targeting significantly reduces irradiation of surrounding healthy tissue, patients treated with conventional radiotherapy systems may be candidates for re-irradiation with the CyberKnife System in the event of recurrence. Each patient should consult with their physician regarding their specific case.