Is Proton Therapy the Future of Cancer Treatment?
In the field of cancer cure, proton therapy/ proton radiotherapy is an innovative form of particle therapy which uses high powered beams of protons for irradiating diseased or cancerous tissues. Proton therapy uses these charged particles for delivering radiation doses which are deposited in the targeted area over a meticulous range of depth, meaning that there is minimal exit, entry, or scatterings of the radiation dose.
Proton Therapy aka Proton Beam Therapy is an advanced type of radiation therapy that has revolutionized how tumors were targeted making the process more precise and effective. Proton therapy basically operates through protons instead of x-rays for treating cancer.
So, what is a proton?
A proton can be defined as a positively charged subatomic particle that has a smaller mass structure than a neutron. The high energy produced by protons is powerful enough to destroy cancer cells.
How proton therapy functions:
A machine called a cyclotron or synchrotron is used for increasing the speed of protons. This high-speed movement of protons produces a form of powerful energy that pushes them to travel to the coveted depth in the body. Upon reaching the desired position, these protons start delivering targeted doses of radiation into the tumor.
How is proton therapy treatment given to the patient?
Patients receive proton therapy in an exclusively designed treatment room. For each treatment, the health care team at the hospital will place the patient inside the device on the treatment table. For treating areas around the head & neck like the eye, the patient will be positioned on a special chair.
Then the oncologist and the patient will have a discussion based on which a treatment plan is created. The doctor will use x-ray images or other image-based tools for marking the parts of the patient’s body that are affected by cancer.
The treatment team will ensure that the patient is in the right position before starting the treatment. This therapy involves the use of a laser for centering the marks that are placed on the patient’s body or the device during the planning scan for the treatment.
The team have already taken the x-rays or CT scan images of the patient before the treatment, which will help them position the patient in the exact direction to receive the beams on the targeted tumor so that the protons can attack it without damaging the nearby tissues.
The proton treatment room also comprises of a gantry. It basically rotates around the patient. This way, the treatment can be delivered to the cancerous tumor from the most prominent angles. Throughout the treatment, the gantry will rotate continuously around the patient to help the doctor determine if the equipment’s nozzle is in the right position or not. The nozzle is the area which will produce the proton beams out from the machine.
Once the patient is positioned correctly, the doctors will go to the delivery control room outside that has a connecting glass to the machine room, from where the doctor will start the therapy. The control room comprises of machine controls that will be used to deliver the proton therapy. The doctors will see and hear the patient from the control room through a video camera that is placed inside the other room.
Now the therapy will be started, and the protons will travel from the machine, and then the magnets will direct them to the desired position of the tumor. Sometimes the gantry can also be used for delivering better efficiency. During the treatment, the patient should stay still and avoid any form of movement as it can disturb the positioning of the proton beam.
Time Required for delivering proton therapy
In general, a proton radiation therapy can last for 15 to 30 minutes, starting from the time the patient enters the treatment room. The duration of the treatment is subject to change as it depends on the organ/part of the body that is being treated and the number of sessions that will be required. It can also depend on how easily the doctors are able to see the tumor in site with the help of images produced by the x-rays and CT scans during the positioning process.
Proton Therapy VS Tradition Radiation Therapy
Conventional radiotherapy engages with X-Ray radiation energy for treating cancer and benign tumors. In doing so, it is likely to damage the surrounding healthy tissues by delivering radiation in a radius, which might include healthy tissues around the tumor. In contrast, proton beam as discussed above delivers radiation dosage only to the tumor maximizing the likelihood of cure while minimizing the damage on the surrounding of the healthy tissues.
In addition, another chief advantage is the proper distribution of the radiation dose. A low dose of proton beam/ radiation is emanated at the targeted body surface that is followed by a sharp, powerful burst once it gets in contact with the tumor, with the negligible amount of radiation travelling beyond the desired target.
Conventional radiation is extremely penetrating and delivers the dose of radiation throughout the volume of tissue exposing healthy tissues. However, 0.5 to 3 cm of radiation is delivered from the patient's skin, depending on the amount of energy it was given. It gradually loses this energy until it reaches the desired target. Tumors are usually located at depth, and because conventional radiation is actively interacting with healthy outer cells, it ends up transferring the a small amount of remaining dosage of ionizing radiation to the deeper cancerous cells.
Proton therapy limits the side-effects of radiation, by preventing its doses from going outside the targeted tumor. In traditional radiation therapy, X-Rays are delivered to patients mainly from outside the body, which cannot deliver targeted preciseness and results in damaging all the nearby healthy tissues surrounding the tumor, causing severe side-effects that can be experienced 6 months after the therapy.
Benefits of Proton Therapy
Compared to conventional radiotherapy, proton therapy has the following benefits:
The nearby organs/ tissues surrounding tumor receive less than 60% of radiation during proton beam therapy causing minimal damage to the healthy tissues. This lowers the risk of damage making it more effective.
Because it delivers radiation so precisely on the target, it can be used for providing higher radiation doses on the tumor. This, therefore, increases the chances that tumor cells targeted by the therapy will get destroyed in lesser sessions.
It may cause few or less severe side effects, like fatigue, low blood counts, slight nausea during or the after treatment.
Types of Cancer that can be Treated via Proton Therapy
Proton treatment is effective for treating or managing benign or malignant tumors that have not started spreading or are present in the delicate organs of the body like the spinal cord or brain. It is also used for the treatment of children as it reduces the chance of harming healthy, growing tissues. Proton Beam Therapy can also be used for treating eye cancer, including orbital rhabdomyosarcoma and retinoblastoma.
Others might include:
Cancers present in the central nervous system, including chondrosarcoma, chordoma and malignant meningioma
Eye cancer, including choroidal melanoma or uveal melanoma
Head & neck cancer, including paranasal sinus cancer, nasal cavity and some nasopharyngeal cancers
Spinal and pelvic sarcomas, a type of cancers that develops in the bones and the soft-tissue
Non-cancerous brain tumors
What should patients expect while receiving proton therapy?
Proton Therapy is delivered to a patient usually in an outpatient setting. Patients don’t have to stay at the hospital for their treatment. However, the number of sessions and the frequency of proton beams used on each patient is subject to vary depending on the type and size of the tumor.
Sometimes, oncologist delivers proton therapy in portions of 1 to 5 proton beam treatments. They basically use large daily doses of radiation on the patient that automatically reduces the number of treatments/ sessions required. This process is called Stereotactic Body Radiotherapy. And Radiosurgery is when a patient receives a single high dose of radiation.
Ongoing research on Proton Therapy
Several researches and clinical trials have been going on comparing proton therapy with x-ray treatments. A clinical trial consists of a research study which involves test subjects, typically real people (patients). These treatments are being thoroughly studied for several reasons:
Proton beam therapy has a higher risk compared to x-ray radiation when used on moving organs like lungs. The constant movement within the organ will prevent the beams to target the tumor, not delivering the right amount of dose.
So, far Proton beam therapy has successfully treated certain cancers. But the medical world has been able to achieve excellent results in treatments of nearly all types of cancers with minimal risk of any significant side effects from advanced radiation therapies. Now for these tumors, research and clinical trials are required for finding out which therapy is better for treating which type of cancer. This is important because of the cost proton beam therapy is way more expensive than radiation beam therapy. And this a major reason why most hospitals haven’t setup a proton care center.
Patients can contact Medmonks to gain more information about Proton Therapy and its advantages.
