Proton beam therapy is a type of radiation therapy that uses protons rather than X-rays for cancer treatment. A proton is a positively charged particle; it destroys cancer cells at high energy, the treatment using proton therapy is done alone or it can also be combined with X-Ray radiation therapy, surgery, chemotherapy or immunotherapy. Proton therapy is the most advanced form of radiation therapy; it has very limited side effects of cancer treatment. It is mostly preferred to fight cancers where the side effects are particularly unwanted like the brain, prostate cancers, and pediatric cancers etc. this
therapy is growing but still not accessible everywhere.
How does proton therapy work?
Proton therapy and X-ray therapy work in a similar way, where the external beam radiotherapy is designed to kill cancer cells. In both the therapies the tumor is targeted with a radiation beam made out of ionizing particles that damage DNA of cells. It will kill or prevent them from proliferating. In the process of treatment, the proton beam also irradiates some healthy tissues which may induce fatigue, skin irritation or certain side effects related to the irradiated organs. Secondary cancers can also develop, so to reduce these types of side effects and give time to normal cells to heal, this therapy is given in small daily doses, five days in a week which is known as fractionation. With this treatment, there is less radiation dose outside of the tumor. Whereas, in X-ray therapy, it continues to give radiation doses until it leaves the person’s body and damages the nearby healthy tissues.
How is proton radiation therapy treated?
The patient will lie on a couch and fitted with a device that helps you stay still. And then, an external source of radiation generated by a particle accelerator is pointed at a particular part of the body, focusing the radiation beams directly at the tumor area. Depending on the depth of the tumor the radiation energy rays will differ. Low energy rays are used to treat skin cancer and superficial structures and high energy rays are used to treat deep- seated tumors such as bladder, bowel, prostate, lung or brain.
Duration of each treatment
The treatment duration lasts about 15- 30 minutes. The time also depends on the area of the body being treated and the number of treatments required. Every time you undergo the treatment the time may vary because the doctors need to target different areas that require other radiation fields. This treatment may require using different kinds of proton beam segments, for example, one treatment may deliver high energy dose to lymph nodes and healthy tissues around the tumor that consists of tiny amounts of the tumor. Another day it may need to deliver a radiation dose to the main tumor.
Advantages of proton therapy
The main advantage of this therapy is dose distribution, allowing the doctors to precisely aim the highest dose to the tumor and avoid healthy tissues. It reduces overall toxicity. It reduces the probability of short or long term side effects on other healthy tissues or organs around the tumor. It can be used to treat recurrent tumors. It can be used for patients who already undergone radiation. Quality of life will be improved during and after the radiation.
This therapy is good for cancers with limited treatment options, unlike x-ray radiotherapy which has an unacceptable risk to the patient.
The proton therapy is very much ideal for pediatric tumors as a child’s growth implies a steady growth of mitosis; the child’s cells will be as vulnerable to ionizing particles as proliferating cancerous cells. The proton therapy helps to aim the beams only at the tumor to avoid any damage related to growth abnormalities, cognitive impairments, cardiac damage, etc.
Side effects of the treatment:
The treatment has no serious side effects. It is painless, after the treatment you may experience fatigue, skin irritation, swelling, dryness, or blistering. You may have side effects if you are also receiving chemotherapy.
Types of cancers treated by proton therapy
The therapy is used to treat tumors that have not spread and are near important parts of the body such
as the brain, spinal cord, and eye.
It showed promising results in treating some tumors such as prostate cancer, brain, head, and neck, base-of-skull tumors, and lung tumors, tumors near the spine, pediatric cancer, gastrointestinal cancer and melanoma of the eye.
Apart from cancer, proton therapy has been effectively used in treating Parkinson’s disease, epilepsy, macular degeneration, arteriovenous malformations, severe rheumatologic conditions and seizure disorders.