Targeting Brain Cancer -- In-depth Doctor's Interview

20 March 2008

John Suh, M.D., a radiation oncologist, explains Perfexion, a new way more targeted way of treating brain cancer.

Tell me about this new way to target radiation into the brain.

Dr. Suh: It really is building on an historical platform in trying to deliver the treatment more effectively and efficiently. The gamma knife actually has been around for about 40 years. The Perfexion represents a new generation of the gamma knife that allows us to better sculpt the radiation beam, increase patient comfort, decrease patient time and allow for treatment of lesions throughout the head. So it really allows for greater flexibility.

What is the gamma knife?

Dr. Suh: Gamma knife is a tool that allows physicians to deliver a high dose of radiation to a small target. It was developed in the 1950s to try to minimize the effects of surgery.  The potential advantages of the gamma knife compared to traditional brain surgery include no surgical incision, no hospitalization and short recovery time. In the late 1960s, the gamma knife was developed to try to develop a nonsurgical tool so that no incision would be required to treat brain disease in patients. It really has had a long track record worldwide with over 400,000 patients have been treated with the gamma knife.

What is the difference between the early gamma knife and this?

Dr. Suh: There are some key differences. The main difference between the Perfexion and the older gamma knife units is that this unit is more automated. Because it is more automated, it allows for greater treatment flexibility, decreased treatment time and increased patient comfort.

Now this can get the tumors that maybe you wouldn't be able to operate on? 

Dr. Suh: Yes. Historically, with our older version of gamma, there are some situations where we could not technically treat a certain target or lesion. With this new version, because the treatment area is so much larger we are able to treat many other lesions that we previously couldn't reach. 

How does it work?

Dr. Suh: The gamma knife uses 192 individual beams of radiation that all meet at one point. We vary the position of the radiation beam by the robotic table, which moves up and down, or side to side. So the goal is to get a very high dose radiation to the tumor or target and more amounts of radiation outside the area. 

So you are really protecting the healthy brain tissue?

Dr. Suh: Yes. We have a 192 individual beams of radiation that all meet at one point.  Any one beam of radiation causes very little damage but having these radiation beams all converge or meet at one area, allows for maximum damage to that target.

Could this be used anywhere on the body?

Dr. Suh: The gamma knife is restricted to treatment in the brain and base of skull area.  There are some other technologies that allow us to treat other parts of the body, but the gamma knife has been a platform which we have used to help develop treatment for other parts of body parts with this sophisticated type of radiation.

What are the side effects of putting radiation into your brain?

Dr. Suh: The side effects in general tend to be pretty mild to modest. If you compare the side effects to conventional surgery, the side effects appear to be much less compared to regular surgery.

What are the options for someone with a brain tumor?

Dr. Suh: Typically, for a brain cancer patient, the options we think about include surgical removal, chemotherapy and some form of radiation therapy. 

Is this the last effort?

Dr. Suh: The gamma knife can be used actually in several scenarios. It can actually be used as the upfront treatment or the main treatment. It can be used adjuvantly in conjunction with surgery or chemotherapy or it can be used in the recurrent setting. So the nice thing about the gamma knife is that it allows us to treat the patients in various scenarios depending on the situation. 

What do you like about this?

Dr. Suh: The big advantage of the Perfexion compared to our older gamma knife units is that it really increases patient comfort, decreases treatment time, decreases radiation exposure to the patient and the medical workers. It also allows for greater flexibility in what lesions we can treat in the brain since we have really no limitation in terms of what structures we can reach within the brain. So really it allows for a much better platform to treat patients.

What are the side effects of brain radiation?

Dr. Suh: The side effects from whole brain therapy and gamma knife radiosurgery are different. Both have its role in the management of patients with brain cancer and it really depends on the individual. 

How risky is surgery?

Dr. Suh: Surgery has been kind of the gold standard in terms of treatment for patients with a single lesion in the brain. However, there is new data coming out with the results of gamma knife radiosurgery, the results seem to be comparable if not better than surgery in certain situations. 

How long does the gamma knife procedure take?

Dr. Suh: Depends on the size of the lesion. The treatment sometimes can vary; it could be a very quick treatment, like ten minutes, or it can be a longer treatment, like two hours. It really depends on the number of lesions, the size of lesions and how complex a treatment it is overall. 

Is it a one time treatment?

Dr. Suh: It is typically a one time treatment, although we will treat patients on multiple occasions with the gamma knife if they pop up with other lesions in the brain, which are still treatable with the gamma knife.

Commento Personale: Ricordo che questo tipo di radiochirurgia (utile per colpire piccole masse, anche recidive) è disponibile da poco anche in Italia. Personalmente ritengo sia da preferire la CyberKnife alla Gammaknife Per maggiori informazioni si riveda questo intervento. E’ utile osservare anche questo intervento, e quest’altro intervento.

Source Ivanhoe.com