Proton Therapy: The latest weapon in the fight against cancer

Baptist Health South Florida recently invited me to the grand opening of their new Miami Cancer Institute to meet Pete, their new cancer-fighting proton therapy machine and I was impressed not only with the technology but also with the facility.How can Pete change the way cancer is treated in South Florida?Cancer is one of those words. It elicits reactions and emotions no matter who you talk to. One thing everyone agrees on is that they want it gone. According to new statistics from the CDC, cancer is the number two cause of death in the US but as the population ages and heart disease-related deaths continue to decline, cancer will soon become number one. What are the common treatment options?There are three ways that cancer is normally treated in this country and around the world: surgery, chemotherapy and radiation therapy but there is a technology that is gaining traction and showing impressive results called proton therapy.

What makes proton therapy better for destroying cancer tumors?

Proton therapy is the most advanced radiation therapy available in the world but before we get into the specifics of how proton therapy works and how it’s used to fight cancer, let’s get through some refresher basics like what are protons? If you have a PhD in Physics, you can skip this next paragraph.Protons are super tiny particles which have a positive charge and are smaller than an atom as they are found in the nucleus. They are so small that you can’t even see them with an electron microscope. So you have an idea, if an atom is the size of a football stadium, a proton is smaller than a marble. Put that in perspective and now you know how small we are talking.

How are these protons created?

Now, this is the cool part. The machine that wrangles all those protons and their cancer-fighting power is called a cyclotron, which is a particle accelerator that takes up the size of a room. The cyclotron uses very high voltage and very strong magnets to separate hydrogen atoms into electrons and protons and accelerate these protons to extremely high velocities . These protons are then regulated in intensity and channeled to three treatment rooms.

Why are protons better than X-rays?

To establish that, let’s talk about the current most popular form of radiation therapy which uses X-rays. When a tumor is treated with X-ray photons, the radiation goes through the body in a continuous beam and causes damage through the entry and exit paths. Basically, the cells in the path before and after the tumor receive radiation. That’s why there are many inoperable tumors that can’t be treated with traditional X-ray radiation, especially those in sensitive areas like the brain and the spine because the collateral damage would damage vital organs or tissues.Protons are better for treating these types of tumors due to a phenomenon discovered in 1903 by Sir William Henry Bragg. This property is called the Bragg peak and it proved that protons reach their peak of energy right before they stop.Think of a pitcher on the mound that’s launching a straight ball that goes right through the batter to be caught by the catcher, this would be an X-ray. If the pitcher could throw the ball and magically stop it when it reaches the batter, this would be a proton. I don’t know if this is the best example but you get the simple idea, X-ray passes through while protons stop at their peak intensity when they reach the set target, in this case, the tumor. But wait, it gets better.Due to its precision for treatment and minimal damage to surrounding tissue, Proton therapy is currently being used to treat specific solid tumors in delicate areas such as the brain, the spine and certain cancers in children where X-rays cannot be used.

Minimizing side effects

The proton beam is specifically configured to attack the shape and size of each tumor since the proton therapy machine can target a tumor with sub-millimetric precision. This allows it to target only the tumor and spare the healthy tissue around it.How can it achieve such precision if just the act of breathing can displace the chest by a few millimeters? The solution is pretty clever. The treatment room has 2D and 3D imaging technologies such as X-rays and CT to ensure the accuracy of the location.The robotic patient positioner, where the patient lays to receive the treatment adjusts itself with incredible accuracy by moving and rotating horizontally, vertically and even changing the inclination. The big electron gantry then can move in a circular motion around the patient to achieve the optimal angle of attack. Each treatment is comprised of several sessions depending on the individual tumor so it’s important to find the exact point of treatment every time.

Pencil beam scanning

This is one of the coolest parts of this cancer-destroying mega machine. Think of an inkjet printer where the printing head goes pixel by pixel creating a perfect drawing. While undergoing treatment, the tumor is targeted with a really thin proton beam that follows its shape. The beam goes through the tumor layer by layer similar to a 3D printer, as if it were drawing it with an incredibly precise pencil. This allows it to trace very complex shaped tumors while adjusting the intensity of the treatment in every step as set by the doctors.

How different is the patient experience from traditional X-ray radiation therapy?

According to Sloan Kettering Memorial Cancer Center, the main proton therapy experience is quite similar with the same number of treatments and session times so the actual experience looks pretty much the same.

OK, if proton therapy is so good, why isn’t everyone using this technology?

The answer is simple. Cost. Baptist bought the Proteus®PLUS three-gantry room configuration, is spending around $130 million on this machine alone and around $430 million on the Cancer Institute overall. Not only to have Pete, but all the other cancer fighting technologies and their best oncologist under one roof. This is a substantial investment that very few centers around the world even have the possibility of making.The Miami Cancer Institute with its advanced technology and its partnership with the Sloan Kettering Memorial Cancer Center is going to become a destination for patients from all over the Caribbean, Central and South America as it’s the southernmost point of the United States with this sophisticated equipment. It is one in less than a dozen facilities in the United States with this technology and the only one in South Florida to have it.

In conclusion

This is of those cases where we hope that none of us ever has the need to visit this center but in the event that we do, it's truly reassuring to know that this state of the art technology, facility and its doctors are right in our own back yard.