Dangers of Proton Beam Therapy

Even though proton beam therapy limits the radiation to healthy organs and presents fewer side effects as a result, it is still a relatively risky medical treatment for certain types of cancer. As the therapy involves nuclear radiation (like all other radiation-based cancer treatments), proton therapy is likely to have some unwanted side effects. 

Notably, these adverse effects and risks can vary significantly from one patient to another, depending on the dosage administered, the tumor’s location, and the clinical response of an individual patient. When the doctors may identify severe adverse reactions in a patient, they will provide another special treatment to relieve those effects.

Long-Term Risks of Treating Brain Tumor with Proton Beam Therapy

After the cancer radiation treatment is completed (using the proton beam technique), long-term side effects can occur months or even years down the line. The risks vary depending on the amount of radiation used and the areas exposed to radiation. As the radiation techniques continue to improve and evolve, it becomes difficult to predict with accuracy how it will affect a patient in terms of post-treatment complications and side effects. While the advocates of proton beam therapy claim that the long-term risks of the treatment are low for brain tumor patients, it is vital for patients and their caregivers to have an understanding of the potential long-term dangers to the patient’s health.

• Risk of developing secondary cancer - There is some amount of risk that the patient may develop secondary cancer in or near the field of proton beam radiation. When healthy tissue is exposed to radiation, it may develop second cancer. The latest radiation techniques are specifically designed to limit such exposure. However, it may not always be possible to avert all exposure, and despite the best precautions, the patient may still develop second cancer.
• The growth of necrotic tissue - In some rare cases, a mass of dead tissue – necrotic tissue – may form around the tumor area. This could take months or years to develop after the proton beam radiation therapy has been completed. Surgery may be required to remove this dead tissue.
• Harm to healthy brain tissue - This occurrence is rare, but sometimes the healthy brain tissue may be damaged during the proton beam therapy treatment, leading to seizures, headaches, or even death of the patient.
• Loss of brain function - In some cases, certain brain functions can be negatively affected due to the brain’s exposure to excessive proton beam radiation. Depending on the amount of radiation given and what the treated brain area controls, these symptoms can vary from one patient to another.
• Damage to the pituitary gland - There is a potential risk that the pituitary gland, along with the other areas of the brain, could be damaged during the proton beam treatment. It can negatively affect the patient’s hormone levels, including sex and thyroid hormones. It can also cause potential fertility issues in women and sexuality concerns in men. These effects may have to be managed later by taking synthetic hormones.

Common Side Effects for Intra-Cranial Tumors

• Fatigue and lethargy - These conditions may not be much noticeable, but low-key fatigue can occur during or after the full course of radiation treatment. Gentle exercises like walking are recommended to ease the symptoms.
• Headaches and nausea - When the area around the tumor swells due to exposure to proton beam therapy radiation, a patient could experience symptoms such as nausea, vomiting, and headaches.
• Irritation of mucous membranes - If the tumor is located close to the upper spine, irradiation may cause inflammation of the pharyngeal mucous membranes.
• Hair loss - As a temporary side effect, patients can experience alopecia or hair loss. When the radiation rays pass over the brain, the hair in the said region can fall off but grow back within 3 to 6 months.
• Loss of appetite and taste - These symptoms may appear independently or together, but they improve gradually within a few weeks or months after the proton beam treatment.
• Redness on the skin - Also known as erythema, this is a temporary skin redness condition, which goes away within two to three weeks. After proton beam radiation, direct sun exposure should be avoided. Wearing headgear such as a hat or scarf for several months after a brain tumor treatment is recommended to prevent harmful sun exposure.
• Depression - Depression and anxiety may occur as additional side effects of the proton beam treatment, which can lead to eating and/or sleeping issues. Proper psychological support is recommended to ease these symptoms.

Risks of Eye Tumor Treatment with Proton Beam

Although there is a low risk of unwanted side effects in the early stages of proton beam therapy for eye tumors, the possibility cannot be ruled out. Irritation of the cornea or swelling of the eyelid as a result of prop placement can occur. That’s why the services of an ophthalmologist may be required along with a radiologist to monitor the patient’s eye condition and identify any complications early. The patient may also experience temporary blurred vision in the treated eye right after the proton beam treatment or a simulation session.

Lack of Research to Compare Data

When it comes to best practices regarding proton beam therapy, there is not much research data available. As a result, it takes an extended trial and error process to determine the optimal radiation dosing for a particular patient. There is no established protocol for proton beam therapy dosage due to a lack of data. At this moment, there are no research studies that can directly compare the safety and efficacy of proton therapy to traditional therapy options for treating cancer.

Limited Efficacy of Proton Beam Therapy: ECRI Report

According to a report published by the ECRI (formerly, the Emergency Care Research Institute) in 2010, proton beam therapy was only effective in about 15% of the total cancer cases. A number of healthcare experts and researchers are concerned that people are relying more on scientific theory and less on actual clinical data to support investment in the expansion of proton beam cancer treatment centers across the country. According to Diane Robertson, director of health technology assessment at the ECRI, one of the biggest concerns about proton beam therapy is that there are no studies that compare it to traditional therapy. She also said that this lack of data leads to other issues. For instance, it is not possible to create dosing levels and best practices because they don’t yet know what the optimal dose is.

Few Randomized Trials

Elise Berliner, director of the Agency for Healthcare Research and Quality's technology assessment program, is in agreement with Robertson. She pointed to a 2009 report by AHRQ, Particle Beam Radiation Therapies for Cancer, which concluded that only 8 out of 243 proton therapy studies were randomized trials. That means only 8 trials compared the proton therapy treatment with other radiation treatments of certain cancers. Another salient aspect to note is that a very small number of patients were enrolled in these trials. Only 15 to 393 volunteers were part of these randomized studies. Also, these trials failed to report any significant differences in the cancer-specific survival rates of the participating patients.

Key Takeaway

Clearly, proton beam therapy offers a strong promise to treat brain tumors and certain other types of cancers. However, aggressively promoting a treatment for commercial benefit without first adequately establishing its clinical safety and risk profile could do more harm than good to the patients in the long run.

In this video, Dr. Ramesh Rengan with the Seattle Cancer Care Alliance explains how this radiation treatment can precisely target cancer and minimize radiation to healthy tissue.

Sacramento Products Liability LawyerI'm Ed Smith, a products liability lawyer in Sacramento. Proton beam therapy can cause long-term risks and side effects. If you or a family member believe you have developed complications after using proton beam radiation treatment, you can call me for free, friendly advice at (916) 921-6400 or (800) 404-5400.