What are the side effects of proton beam therapy?
By Christina L. Mershell
Proton Beam Therapy: Unlocking a Future with Fewer Side Effects
When faced with a cancer diagnosis, the impact on one's health and well-being become a paramount concern. The question of how treatment may affect your life, both in the short term and for years to come, looms large. Understanding the potential ramifications of cancer treatments is a crucial step in deciding the right path for your unique journey.
Individuals must have open, honest dialogue with their healthcare professionals about treatment-related side effects. Each cancer diagnosis and treatment journey presents a distinct set of side effects. For example, the experience of someone undergoing treatment for prostate cancer will differ from that of a breast cancer patient. Hence, personalized medical advice is indispensable to comprehend one's situation and expectations.
The Science Behind Side Effects of Radiation
Radiation therapy is an effective treatment in the battle against cancer; however, it has side effects. Radiation therapy inflicts damage on cells, which is essential to eradicate cancer cells, but this collateral damage can result in treatment-related side effects. One challenge radiation oncologists deal with is delivering enough radiation to the targeted tumor while reducing and eliminating radiation to the surrounding, non-cancerous, tissue. While many great radiologic technologies reduce high radiation doses to surrounding tissues, only proton therapy can stop the radiation at the tumor site. Because of the stopping power of proton therapy, patients often experience fewer side effects from tissues that are further away from the target area. For example, a patient receiving radiation therapy for a tumor on the left side of the jaw will have reddening of the skin and a sore mouth at the target. The difference with proton therapy is those side effects stay on the left side of the jaw, while other x-ray-based treatment options will impact the entire mouth.
Short-Term Side Effects of Proton Beam Therapy
Proton beam therapy typically spans 4 to 8 weeks, with daily sessions targeting the tumor. Patients may experience side effects while undergoing treatment. If there are side effects, they typically happen later in treatment and are resolved with the help of the radiation oncologist. Thankfully, these side effects tend to heal within a few weeks of completing treatment.
Please note that all patients are unique, and treatment-related side effects are very different based on the location of the treatment. A radiation oncologist should explain specific side effects that may occur. Here are some common short-term side effects patients might experience while receiving proton beam therapy.
- Brain Cancer – reddening of the skin and loss of hair
- Breast Cancer – reddening of the skin
- Head and Neck Cancer – reddening of the skin, sore throat, and difficulty swallowing
- Lung Cancer – reddening of the skin and coughing
- Prostate Cancer – reddening of the skin and urinary urgency
Long-Term Side Effects of Proton Therapy
Proton beam therapy, like other radiation therapies, carries a small risk of long-term complications. These may manifest months or years after treatment, known as radiation-induced late effects. However, the risk of such complications is notably lower with proton therapy compared to traditional radiation, owing to reduced radiation exposure to healthy tissues near the tumor.
Proton therapy's precision in targeting cancer cells while sparing surrounding healthy tissues reduces secondary side effects. This can be particularly beneficial for individuals with pre-existing health conditions. For example, a patient receiving treatment for left lung cancer might be very concerned about reducing or eliminating radiation to the right lung. Proton therapy can target the tumor and eliminate radiation to the unaffected right lung.
The overarching goal is to cure cancer, and proton therapy offers radiation oncologists a means to achieve this while minimizing long-term side effects.
Addressing Secondary Cancers
Radiation-induced cell damage, while essential for eradicating cancer, also carries the potential risk of causing secondary cancers in adjacent normal tissues. Radiation oncologists work diligently to limit unnecessary radiation exposure to healthy body tissues, reducing the risk of radiation-induced cancers. Proton therapy effectively reduces radiation doses to normal tissues.
Minimized Risk and Promising Research
Proton therapy reduces the risk of secondary cancers for many patients and research is ongoing to determine the extent to which proton beam therapy may limit the chance of cancer occurring after a patient receives treatment. In 2020, researchers at Stanford University published a promising study in the American Cancer Society's academic journal, Cancer. In a study of more than 450,000 patients, people who received proton beam therapy had a significantly lower risk of secondary cancer compared to similar patients who received traditional radiation therapy.1
Personalized Approach to Proton Therapy
Every cancer affects distinct parts of the body, and each patient's response to radiation treatments may vary. When determining the best treatment approach, radiation oncologists consider each patient's specific case, offering the most suitable option. Numerous studies reinforce the notion of reduced side effects with proton therapy.
What If Proton Therapy Isn't Right for Me?
While proton therapy demonstrates great promise to reduce both short and long-term treatment side effects, it is not always the most appropriate choice for patients. In some cases, proton therapy does not offer significant enough benefits over X-ray based treatment options. Please talk to a radiation oncologist who offers proton therapy to determine if it is a good treatment option for your diagnosis.
- A 2023 study in the International Journal of Particle Therapy found that proton beam therapy was the “preferred modality for bilateral breast cancer treatment when available.” This was due to the reduced radiation dose to critical organs and tissues.2
- Proton beam therapy research shows low rates of side effects assessed by physicians, as well as patient-reported outcomes for patients with prostate cancer.3
- Another recent study was completed by UF Health Proton Therapy Institute radiation oncologists, in conjunction with specialists at other proton therapy centers. This study showed promising overall survival rates for people with lung cancer, as well as no severe short-term esophageal side effects.4
- In addition, minimal risk of serious brainstem injury for patients with brain cancer was reported in a 2022 study published in Acta Oncology.5
Reviewed Nov. 20, 2023, by Romaine Charles Nichols, Jr., MD
About the Author
Christina L. Mershell is a patient educator at the UF Health Proton Therapy Institute. She provides patient orientations, builds referral relationships, and increases public awareness about proton radiation therapy for cancer treatment through community events and presentations.