What to know about proton therapy for breast cancer
Unlike traditional radiation therapy, proton therapy does not use X-rays. Experts think that proton therapy may be safer than other radiation therapies because it targets a specific area and has less of an impact on the healthy tissue around cancer cells.
In this article, we discuss proton therapy for breast cancer. We look at what it is, how it works, the procedure, and effectiveness.
What is proton therapy?
Proton therapy may improve breast cancer survival rate.
Proton therapy is a precise form of beam radiation therapy that uses energy from protons, or positively charged particles.
Because of its precision, proton beam therapy may improve survival rate by improving local tumor treatment and reducing injury to other organs, leading to fewer radiation-related side effects.
Having radiotherapy can increase the risk of heart-related complications. Proton therapy has a lower risk of these complications because it delivers less radiation to the heart compared to standard photon radiation therapy, according to a 2018 systematic review.
A review reports that the first recorded use of proton beam therapy in a hospital setting was in 1991 in Belgium. Since then, doctors have used proton beam therapy to treat thousands of cancers worldwide.
Proton therapy can treat solid tumors, but it cannot treat cancer cells that have metastasized to different parts of the body.
How does it work?
Radiation specialists use a synchrotron machine to accelerate protons up to 60% the speed of light. The speed of the protons creates a high amount of energy and pushes the protons through a nozzle directed at the body.
The protons travel to a specified depth in the body, where they deliver high doses of radiation to the tumor.
Radiation creates breaks within the DNA inside the cancer cells to destroy them.
When do doctors use proton therapy?
Due to its precision, doctors recommend using proton therapy when trying to spare healthy tissue near the tumor site.
For example, proton therapy has specific benefits in treating eye, brain stem, and spinal cord cancers. Saving healthy tissues in these sites is of the utmost importance.
Proton therapy offers a safe alternative to standard radiation therapy when treating early-stage breast cancer.
A doctor may recommend using radiation therapy after a lumpectomy or mastectomy to kill any remaining cancer cells. Proton therapy is especially advantageous when treating breast cancer on the left side because it presents less risk to the heart.
Proton beam therapy can also treat the following types of cancers:
- head and neck cancers
- nose and eye cancers
- lung cancer
- esophageal cancer
- breast cancer
- stomach cancer
- prostate cancer
- anal, rectal, and bowel cancers
- bladder cancer
- pancreatic, gastric, and hepatobiliary cancers
- liver cancer
- kidney cancer
- spinal cord cancer
Proton therapy vs. standard radiation therapy
Both photon therapy and standard radiation therapy use radiation to damage or destroy cancer cells. However, these treatments use slightly different methods to deliver radiation.
Standard radiation therapy delivers radiation through high energy particles, such as X-rays or electrons. This method deposits radiation to any tissue along its path, which can harm healthy cells near the tumor.
Due to its accuracy, proton therapy can spare more healthy tissue than standard radiation therapy. It also involves a lower risk of heart-related complications.
What happens during the procedure?
A doctor may recommend a CT scan to locate areas that need proton therapy treatment.
The treatment takes place in a specialized facility equipped with a particle accelerator and a table for the person to lay down on.
A specially trained technician will operate the particle accelerator and ensure the person's safety during treatment.
The whole procedure lasts about 15–30 minutes. This includes the time it takes for the person to get into position and for the technician to make any last adjustments to the equipment. The proton beam exposure only lasts a few minutes.
People usually receive multiple rounds of proton therapy. However, since proton beams can deliver higher doses of radiation with more accuracy, proton therapy usually requires fewer treatments than standard radiation therapy.
How effective is it?
Proton therapy appears highly effective against breast cancer.
According to a 2019 study on 42 people who had received proton therapy after a mastectomy for breast cancer without metastasis, treatment resulted in an overall 3-year survival rate of 97.2%.
A larger-scale 2018 study reports that proton therapy is effective and that there was no significant difference in the survival rates of people who received proton versus non-proton therapy. However, the authors conclude that due to the high cost of proton therapy, doctors should consider it mainly for people who may be at risk for high heart doses of radiation due to the location of their tumor.
Proton therapy can cause side effects similar to those of standard radiation. However, since proton therapy affects less healthy tissue than radiation therapy, it usually causes fewer or milder side effects.
Side effects associated with proton therapy include:
- skin irritation or dryness
People may experience additional side effects if they receive additional chemotherapy or standard radiation therapy.
Risks and complications
Proton therapy offers a safe alternative to standard radiation therapy with fewer, less severe side effects and a lower risk of damaging healthy cells.
Despite these advantages, proton therapy does come with risks and potential complications and is much more expensive.
Proton therapy is a type of radiation therapy that doctors use to treat cancer. It uses high-energy protons to deliver radiation to specific targets inside the body.
Doctors may use proton therapy to kill any cancer cells left over from a lumpectomy or mastectomy for breast cancer.
This method offers more precision and less risk of damaging healthy tissue when compared to standard radiation therapy. This means that proton therapy may cause fewer and less severe side effects.
The advantages of proton therapy make it especially beneficial for left-side breast cancer. Radiation therapy can affect the heart, but due to its precision, proton therapy has a lower risk of damaging the heart and other healthy tissues around the breast. Researchers need to carry out more large-scale studies that include people who are at higher risk for radiation-related cardiac events to determine if proton therapy results in better overall survival for this population.