Cyberknife cancer Surgery | Frequently Asked Questions
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Frequently Asked Question

Q1. What is CyberKnife System?

CyberKnife® Robotic Radiosurgery System is a non-invasive alternative to surgery,fortreatmentof both cancerous and non-cancerous tumors anywhere in the body, including the head, spine, lung, prostate, liver and pancreas. The treatment which delivers beams of high dose radiation to tumors with extreme accuracy, offers new hope to patients worldwide.

Though its name may conjure images of scalpels and surgery, CyberKnife treatment involves no cutting. In fact, CyberKnife is world's first and only robotic radiosurgery system designed to treat tumors throughout the body non-invasively. It provides a pain-free, non-surgical option for patients who have inoperable or surgically complex tumors, or who may be looking for an alternative to surgery.

Q2. How new is CyberKnife technology?

John R. Adler, MD, Professor of Neurosurgery and Radiation Oncology at Stanford University Medical Center, developed the CyberKnife® system in 1987, after completing a fellowship in Sweden with Lars Leksell, MD, the founder of radiosurgery.

Q3. Is CyberKnife safe?

CyberKnife, does not present problems associated with traditional surgery. Mainly, there is no anesthesia or anesthesia after effects, the risk of infection and hemorrhaging are minimized. CyberKnife offers accurate precision within sub-millimeter distances and spares healthy tissues surrounding the targeted area.

Through the use of continuous imaging, CyberKnife® is able to compensate for patient movement, making uncomfortable head frames obsolete. Also, CyberKnife® uses a robotic arm as a radiation source, enabling many different body parts to be treated. This makes CyberKnife® much more convenient than the gamma knife, or other methods of stereotactic radiosurgery.

Q4. How is a CyberKnife "Radiosurgery" treatment different from a traditional Radiation therapy treatment?

Traditional Radiation therapy typically delivers Radiation to a wide field of tissues in the body resulting in the treatment of both the Tumor and a large amount of surrounding healthy tissues. This is necessary because traditional Radiation therapy systems do not account for Tumor motion and are therefore less accurate. These wide radiation fields often increase the possibility of damaging the normal tissues and increasing the risk of side effects following the radiation treatment. To reduce the number of side effects, clinicians were forced to rethink the way traditional Radiation therapy was delivered. As a result, overall Radiation dose was reduced and number of treatments was divided into 30 - 40 sessions, delivered over a period.

Radiosurgery devices, such as CyberKnife Robotic Radiosurgery System, are designed to deliver Radiation with extreme accuracy, targeting Tumor with minimal damage to the surrounding healthy tissues. The accuracy of the CyberKnife system allows clinicians to deliver very high doses of Radiation safely because the size of the Radiation field is small and includes only the Tumor and a small amount of surrounding tissue. This allows for less damage to surrounding healthy tissue and for clinicians to complete treatment in 1 to 5 days as compared to weeks it takes in traditional radiation therapy.

Through the use of continuous imaging, CyberKnife® is able to compensate for patient movement, making uncomfortable head frames obsolete. Also, CyberKnife® uses a Robotic arm as a radiation source, enabling many different body parts to be treated. This makes CyberKnife® much more convenient than the Gamma Knife, or other methods of Stereotactic Radiosurgery.

Q5. How does CyberKnife System differ from other radiosurgery systems?

Unprecedented targeting accuracy Many tumors have proven to move during treatment delivery - even when the patient is immobilized. Using advanced robotic technology and the ability to track tumor motion throughout the treatment, CyberKnife system can deliver radiation with extreme accuracy by automatically correcting tumor movement in real-time. While other technologies rely on static images taken prior to treatment, CyberKnife system automatically tracks, detects, and corrects for even the slightest motion that might occur during treatment delivery.

Unrivaled conformality& dose gradient

Unconstrained by the clockwise / counterclockwise rotations of conventional radiotherapy systems, the robotic mobility of the CyberKnife system enables beams to be delivered from a very wide array of unique angles. By approaching the target from hundreds of different angles, CyberKnife system sculpts delivered dose precisely to the unique contours of the target, while limiting exposure to surrounding critical structures.

Unparalleled healthy tissue sparing

As the only system capable of delivering beams that move real-time with 3D respiratory motion, CyberKnife system significantly reduces treatment margins. With smaller treatment margins, CyberKnife system focuses the prescribed dose to the intended target — not the surrounding healthy tissue.

Q6. What is image-guided stereotactic radiosurgery?

The CyberKnife system uses a distinctive radiosurgery device with a linear accelerator (Linac), which produces radiation mounted on a robotic arm. Through the use of image guided cameras, CyberKnife locates the position of the tumor. The Linac attached to the robotic arm is then used to deliver multiple beams of radiation while minimizing exposure to surrounding normal tissue. With sub-millimeter accuracy, CyberKnife is used to treat vascular abnormalities, tumors, functional disorders, and cancers of the body.

Q7. Has CyberKnife been cleared by the FDA?

Yes, the Food and Drug Administration (FDA) cleared the CyberKnife system to treat tumors in the head, neck and upper spine in 1999 and tumors anywhere in the body in 2001.

Q8. What can CyberKnife treat?

CyberKnife treats intracranial (skull base) benign and malignant tumors, as well as spine tumors and lesions of the cervical, thoracic and lumbar regions.

Some intracranial (head and brain) tumors and lesions that can be treated by CyberKnife are-

• Acoustic neuroma

• Anaplastic astrocytoma

• Arteriovenous malformation (AVM)

• Craniopharyngioma


• Ependymoma

• Gangliocytoma

• Germinoma

• Glioblastoma multiforme

• Glioma

• Glomus jugulare tumor

• Hemangioblastoma

• Hemangiopericytoma

• Meningioma

• Neurocytoma

• Neurofibronna

• Neurofibronnatosis

• Oligodendroglioma


• Pituitary adenoma

• Schwannoma

• Trigeminal neuralgia

• Vestibular schwannoma

Some, extracranial (outside of the head and brain) tumors and lesions that can be treated by CyberKnife are-

• Colon cancer

• Hepatocellular carcinoma

• Nasopharyngeal carcinoma

• Non-small cell lung cancer

• Osteosarcoma

• Ovarian cancer

• Pancreatic cancer

• Prostate cancer

• Renal cell carcinoma

• Squamous cell carcinoma

• Small-cell lung cancer

• Uterine cancer

Additionally, CyberKnife is capable of full-body targeting for-

• Thoracic surgery (lung)

• General surgery (liver, pancreas and breast)

• Head and Neck surgery (laryngeal, nasopharyngeal, glossal)

• Urological surgery

Q9. What are the benefits for patients undergoing treatment with CyberKnife?

Some of these benefits include:

• No incision

• No pain

• No anaesthesia

• No hospitalization

• Little or no recovery time

• Immediate return to daily activities

Q10. What side effects can one expect after a CyberKnife treatment?

Most patients experience minimal to no short-term side effects and often recover quickly. Depending on the treatment site, some patients may experience side effects such as mild fatigue or nausea. Our CyberKnife experts will disclose / discuss all possible side effects prior to treatment.

Q11. Who determines if CyberKnife is an appropriate treatment?

Medical necessity can be determined by a physician or specialist after evaluating patient's condition. CyberKnife is a unique modality and as such only a CyberKnife trained physician can best determine if it is an appropriate treatment for a particular condition. An experienced CyberKnife physician offers best advice and discusses other treatment options.

It is not uncommon for cases to be discussed with various physicians, including patient's primary doctor, before determining candidacy for CyberKnife treatment.

Q12. How many patients have been treated with CyberKnife?

As of December 2010 more than 100,000 patients have been treated worldwide by CyberKnife. More than half of these patients were treated with lesions or tumors outside of the brain and head.No mortality or morbidity data has been reported as a direct result of a CyberKnife procedure.

Q13. If one is currently undergoing chemotherapy, or has undergone proton therapy is one eligible for CyberKnife treatment?

CyberKnife system treats patients that have either gone through chemotherapy or are currently undergoing radiation therapy. It is important for the patients to provide the doctor with their complete medical history, so that doctor can prescribe appropriate treatment course.

Q14. Can the elderly and children be treated with the CyberKnife?

Since CyberKnife is less risky than traditional surgery it can be a suitable option for the elderly or for pediatric cases. Age is not a crucial factor in excluding patients from CyberKnife treatments. In the case of young children, a pediatrician, anesthesiologist and nurse anesthesiologist may be consulted to ensure the safety and comfort of the child during treatment.

Q15. How many times can one receive a CyberKnife treatment?

The frequency of treatments depends on where the tumor is located and what type of tumor is being treated. Most cases receive multi-treatments or can be re-treated with the CyberKnife system.

Q16. What is a CyberKnife procedure like for the patient?

During a typical treatment session, patient lies on a table and wears a custom-fit mesh / facemask or body immobilizer while the robotic arm delivers the radiation.

Unlike conventional surgery, CyberKnife procedures do not require anesthesia, large incisions or blood loss. Mosttreatments last about 60 to 90 minutes per lesion. After the treatment, the patient can go home the same day.

All CyberKnife cases are unique. Factors like the patient's medical condition, ambulatory status, pre-existing conditions, and present treatments are considered during the planning phase. These help doctors formulate an individualized treatment plan. For example, some patients receive a single session of CyberKnife, while others receive staged (over time) treatments. Patients at Medanta CyberKnife Center receive one-on-one consultation pre and post treatment, so that they know what to expect during the process.

Q17. After a CyberKnife treatment, when will my tumor or lesion disappear?

The effects of radiosurgery vary and may occur gradually and over time. The timeframe can range from days, months or years depending on the medical condition targeted. Some tumors may disappear slower than others or may simply stop growing and present no further cell activity. After treatment, patients typically are asked to get periodic images (CAT scan or MRI) of their tumor(s) and additional tests may be required, so the physician can monitor the effectiveness of the treatment.

Q18. Will my hair fall out or burn my skin after CyberKnife treatment?

The radiation being delivered by the CyberKnife is so focused on a specific target that it is highly unlikely that hair loss or skin burn will occur. Typically, the radiation dose administered is not sufficient to cause permanent damage to the skin or hair follicles. In the event that an intracranial lesion being treated is close to the scalp a patch of hair may be effected. The hair grows back. Patients receive instructions before and after treatment and have an opportunity to discuss with members of the medical team, so that they are aware of possible events specific to their case.

Q19. Are CyberKnife treatments covered by private insurance companies?

A CyberKnife procedure at Medanta is cost effective as it is performed on an outpatient basis and does not require hospitalization, anesthesia or rehabilitation. Since CyberKnife technology is new, some insurance companies may not be familiar with it. We request patients to share their information early enough (prior to their treatment) so we can assist with obtaining pre-authorization and meet coverage requirements as much possible. Our TPA desk assists patients with any questions they may have concerning their coverage and out of pocket expenses.

While Medanta cannot guarantee reimbursement from any third-party payer, patients should always consult our doctor in connection with any and all treatment options, and if required, obtain prior authorization from the insurance company once a treatment option is determined.

Q20. Are there CyberKnife patient organizations I can contact for more information?

There are numerous patient organizations that can offer support and education to patients seeking more information on radiosurgery treatment. Specific to CyberKnife is the CyberKnife Patient Support Group, a non-profit organization established in July 2001. This group is dedicated to helping others by sharing personal experiences of patients who have undergone a CyberKnife procedure. You can also visit

Q21. What is the difference between a lesion and a tumor?

A lesion is any focused abnormality in the body, such as a tumor, a blood clot, a cyst, an aneurysm or an inflammatory mass. A tumor is an abnormal collection of cells that has grown due to a change in the cells. Tumors can be either malignant or benign and are a kind of lesion only.

Q22. How is cancer staged and what does this mean?

Staging describes the extent or severity of an individual's cancer. Knowing the stage of the disease helps the doctor plan treatment and estimate prognosis. Staging systems for cancer have evolved over time and continue to change as scientists learn more about cancer. There are many staging systems and some are specific to certain cancer types. The TNM staging system, for example, is used for lung cancer and is based on the extent of the tumor (T), its spread to lymph nodes (N) and its metastasis (spread to other parts of the body) (M). Most cancers can be described as stage 0, stage I, stage II, stage III or stage IV. Physical exams, imaging procedures, laboratory tests, pathology reports and surgical reports provide information to determine the stage of each cancer.

Q23. What are the different treatment options for treating cancer or benign lesions?

The treatment options available vary according to the specific cancer and its location. In general, the treatments can be divided into following categories:

Radiosurgery also known as stereotactic radiosurgery, is a form of radiation and despite its name, is not surgery. It is designed to precisely destroy a tumor or lesion by delivering a very high dose of radiation to the tumor in 1 to 5 sessions over a treatment course of 1 to 5 days. Patients are not required to be hospitalized during treatment and the procedure is almost always performed on an outpatient basis.

Radiation therapy is a form of radiation that is usually delivered 5 days a week over a treatment course of 6 to 8 weeks. Radiation therapy, (as opposed to stereotactic radiosurgery), usually treats larger areas that include not only the tumor, but large amounts of healthy tissues, increasing the risk of possible complications. Patients are not required to be hospitalized during treatment and the procedure is almost always performed on an outpatient basis.

Brachytherapy is a specialized form of radiation therapy that requires the surgical placement of small radioactive sources in and around a tumor. The radioactive sources can be implanted either temporarily or permanently, depending on the nature of the source used. Low Dose Rate (LDR) Brachytherapy delivers a prescribed dose over a longer period of time. Radioactive sources are usually implanted permanently. High Dose Rate (HDR) Brachytherapy uses a different source type that delivers dose over a shorter period of time, therefore HDR sources are usually implanted temporarily. Brachytherapy has been used to treat a wide variety of cancers including prostate, breast, lung, head and neck cancers.

Cryoablation also called cryotherapy, in this a probe is inserted through the skin and into the tumor to freeze the tumor and kill its cells. Placement of the probe requires an incision and can be performed either on an inpatient or outpatient basis depending on the tumor being treated.

High Intensity Focused Ultrasound (HIFU) uses a focused ultrasound beam to kill tissue containing cancer cells. It is not FDA approved in the US, but has been used to treat prostate cancer in Europe. Surgery or surgical resection is an invasive procedure that requires an incision to remove or cut the tumor out of the body. Surgery can be performed on an inpatient or outpatient basis depending on the tumor being treated.

Q24. How much does a CyberKnife treatment cost?

During the consultation process, patients will be told about how much the treatment will cost. Each patient's requirements differ, hence cost estimates depend on treatment assessment done by our doctor.

Q25. Is CyberKnife Radiosurgery cost effective?

Cost studies have shown radiosurgery to be less expensive than conventional surgery because it eliminates lengthy post-surgical hospital stays, expensive medication and sometimes months of rehabilitation.