Many cancers that can be treated with conventional radiation therapy can also be treated with proton therapy. Since proton therapy is associated with fewer side effects and treatment-related complications than conventional X-ray radiation, it can be an attractive treatment option for patients who are at risk for significant toxicity and/or lasting complications from conventional radiation. A proton radiation oncologist can determine if there would be an advantage to proton radiotherapy for a specific tumor.
The following are some of the tumor types that may benefit from the use of proton therapy:
Proton radiotherapy can be beneficial for many types of brain tumors, including glioma, meningioma, ependymoma, medulloblastoma and craniopharygioma. Protons minimize the exposure of surrounding normal brain tissue to radiation, and can decrease the subsequent risk of memory or cognition problems. In addition, the use of protons can allow higher doses of radiation to be used which can be beneficial for tumors such as chordomas or chondrosarcomas.
Most women with breast cancer are best treated with conventional radiation. However, there are situations where protons may be advantageous. These include women who have had a mastectomy (complete removal of the breast), and some cancers of the left breast who may have an increased risk of injury to the heart or lungs if conventional X-rays are used. Clinical trials are underway to study the use of protons when only a part of the breast needs radiation therapy.
Colorectal & Anal Cancers
For some patients with colorectal & anal cancers, proton therapy can decrease the risk of bowel complications, especially when it is necessary to treat the nearby lymph nodes in the pelvis. For patients receiving chemotherapy, proton therapy can minimize chemotherapy’s toll on the immune system.
Patients with localized esophageal cancer often receive radiation therapy and chemotherapy at the same time prior to surgery. Because the heart and lungs are near the esophagus, this can make radiation planning challenging. By reducing the radiation dose to the heart and lungs, proton therapy may minimize the risk of post-operative complications and long-term side effects seen with conventional radiation treatments.
For women with gynecologic cancers, proton therapy can decrease the risk of bowel complications, and minimize the risk of radiation toxicity to the bone marrow which can cause anemia, bleeding and infection.
Head and Neck Cancers
For patients with head and neck cancers, radiation exposure to the saliva glands and mouth can lead to some of the most significant post-treatment side effects. In some instances, proton therapy involves less radiation to these areas, resulting in less pain and better nutrition during treatment as well as a lower risk for chronic dry mouth. Tumors of the nasopharynx, tongue, tonsil, larynx, hypopharynx and thyroid are some of the tumor types that can potentially benefit from proton radiotherapy.
For some lung cancer patients, proton therapy can reduce the risk of injury to the esophagus during radiation and minimizes the likelihood that they will need a feeding tube to maintain their nutrition. Additionally, in patients with chronic lung problems such as chronic obstructive pulmonary disorder (COPD), radiation exposure to the normal lung tissue can sometimes be reduced, minimizing the risk of causing additional breathing problems.
When lymphomas such as Hodgkin’s Lymphoma occur in the chest or abdomen, protons can be used to eliminate radiation exposure to surrounding normal organs. This can be especially important in women, as protons can reduce their risk of subsequent breast cancer or infertility.
While proton therapy is being used for pancreatic cancer, its role in the treatment of this disease is still being defined. Patients with pancreatic cancer may be eligible for participation in clinical trials involving proton therapy.
Protons have been used extensively for the treatment of prostate cancer and are one of many effective treatments for this disease.
Sarcomas require high doses of radiation for the best chance of cure. When sarcomas occur in the chest or abdomen, treatment with conventional X-rays is often limited due to the sensitivity of surrounding organs to radiation. For some of these patients, proton therapy can circumvent these limitations allowing safe, effective treatment for their tumors.
The use of proton therapy can be especially important for children who have cancer. The effects of radiation on healthy tissue surrounding a tumor are often much more severe in children and can have life-long consequences. Proton therapy can minimize radiation exposure to this sensitive healthy tissue, decreasing potential radiation-related problems in these vulnerable patients.
Cancers that recur after previous radiation can be especially difficult to treat. Previous radiation treatment often limits the amount of conventional X-ray radiation that can be used. Because proton therapy is so targeted and keeps radiation away from healthy surrounding tissue, it can sometimes be used to minimize the risks of re-treatment, allowing for more aggressive/potentially curative treatment.