External beam radiation therapy is a non-invasive treatment that benefits many patients with mesothelioma. It is often used before or after chemotherapy or surgery.[1] Radiation therapy may cause side effects, but decades of research have made it safer.[2]
What Is External Beam Radiation Therapy?
External beam radiation therapy utilizes a beam of high-energy radiation from outside the body to kill cancer cells. The radiation comes from a linear accelerator that aims the beam at the patient’s cancer site.
This type of radiation therapy is external, meaning the radiation comes from outside the body. It has to penetrate other tissues to get to the tumors and kill cancer cells.[3]
Types of Radiation Therapy
Most radiation treatment for mesothelioma is external beam, but it is not the only type. All types of radiation therapy work by targeting tumors with a high-energy beam that kills living cells.
High-energy radiation affects both cancerous and healthy cells, although healthy cells recover better. Radiation can also cause cancer in healthy cells. Because it damages healthy tissue, radiation therapy causes several side effects.[3]
All the many variations of radiation therapy can be grouped into two main types:
- External Beam Radiation Therapy. This original type of treatment trains an external beam of radiation on the part of the patient’s body where the tumor has grown. The beam penetrates healthy tissue to get to the tumor and kill cancer cells.
- Brachytherapy. Brachytherapy uses a radiation-emitting device planted inside the patient’s body. The small device is strategically placed next to a tumor. It may be permanent or temporary. Once implanted, the radiation travels only a short distance and is more focused on the tumor.[3]
What Cancer Does External Beam Radiotherapy Treat?
External beam radiation therapy can treat many types of cancer, including mesothelioma. Some of the most common types of cancer it treats include breast cancer, colorectal cancer, esophageal cancer, lung cancer, prostate cancer, and brain cancer.
Advances in External Beam Radiation Therapy
There are several types of external beam radiation. Most techniques developed from recent advances allow medical professionals to deliver external radiation more safely and accurately.
- Three-dimensional conformal radiation therapy uses imaging scans to create a three-dimensional model of a tumor before treatment. This model allows the medical team to use a computer to conform radiation delivery to the tumor’s shape. This conformity results in less damage to healthy tissue. Modulating radiation intensity improves precision even more.[4]
- Proton therapy uses proton beams rather than the photons of traditional radiation treatment. This method damages less healthy tissue than the traditional method.[4]
- Image-guided radiation uses imaging scans or small transponders implanted in the body to guide radiation to the tumor.[4]
- 4D radiation therapy takes image-guided radiation a step further. The computer uses images throughout the treatment, adjusting as it goes. It can even stop if it goes off track. This newer type of radiation is particularly useful for patients with tumors that move. For instance, when a pleural mesothelioma patient breathes, the tumor shifts a little. 4D radiation can adjust to account for that movement.
- Intensity-modulated radiation therapy varies the intensity of the radiation in specific ways tailored to a patient’s unique factors. This allows the radiation specialist to target the tumor with more intense radiation while minimizing the intensity aimed at healthy tissue.
Is External Radiation for Mesothelioma Effective?
External radiation is the most common type of radiation therapy used to treat cancers, but it is not typically a primary treatment for mesothelioma. It is either used after surgery or for palliative care and sometimes before surgery.
After surgery, radiation is used to destroy the remaining cancer cells. Surgery is one of the most effective ways to eliminate mesothelioma tumors; however, it is often impossible for a surgeon to remove every cancer cell.
Radiation after surgery essentially “cleans up” the area, killing any remaining cancer cells. This method extends life expectancy in patients who have undergone an extrapleural pneumonectomy.[5]
Recent research shows that using radiation before extrapleural pneumonectomy is a promising strategy. Called the SMART protocol (Surgery for Mesothelioma After Radiation Therapy), this treatment approach needs more study, but experts recommend it for some patients.[5]
Radiation treatment is also important for palliative care. When a cure is no longer possible, palliative treatments help make the patient more comfortable. External beam radiation can shrink tumors.
Cancer that infiltrates the bone can be quite uncomfortable, and radiation is generally very effective at improving this pain. As a result, patients may breathe easier or experience a reduction in pain and swelling. This is referred to as palliative radiation since the goal is the improvement of symptoms.[6]
What to Expect When Getting External Beam Radiation Therapy
Going through any cancer treatment can be stressful. It helps to know what to expect. These are the typical steps you’ll go through when undergoing mesothelioma radiation treatment:[7]
- The first step involves a consultation with a radiation oncologist. Like the rest of your team, it is helpful to choose a radiation oncologist with experience in treating mesothelioma.
- Next, you will probably need imaging scans. Depending on the type of therapy your doctor intends, this could involve CT scans or MRIs.
- Technicians may mark your skin with ink to help aim the radiation beam.
- They may also fit body molds to help you stay in the correct position during the treatment. These molds also help guide the radiation beam. During the treatment, you will be guided to the correct position and put into the molds.
- The technician or doctor will then leave the room. For their safety, they will watch from a monitor or window during treatment.
- While radiation therapy does not cause initial pain, you will be required to sit still.
The procedure only takes about fifteen to thirty minutes. You may have several such sessions on different days.
What Are the Side Effects of External Beam Radiation?
Radiation therapy may cause side effects, most of which are temporary. Guided radiation, such as three-dimensional and intensity-modulated radiation, minimizes damage to healthy tissues.
Because fewer healthy cells are affected, there are milder side effects. Possible acute side effects include irritation, burning, and hair loss at the radiation site.[7]
What Are the Most Common Side Effects of External Beam Radiation?
Patients undergoing radiation often experience a loss of energy, which is one of the most commonly reported symptoms. Damage to the skin where the beam is aimed and penetrates is also common.
Which Side Effects Are Specific to Mesothelioma Patients?
Therapy to the chest area, as when treating pleural mesothelioma, can cause inflammation of the lungs. Lung inflammation can lead to cough or breathing difficulty.
For peritoneal mesothelioma, radiation to the abdomen can harm the bowels or bladder, leading to digestive issues or incontinence. Rarely, radiation therapy leads to secondary cancer.[8]
Are You Radioactive After External Beam Radiation?
No, you do not remain radioactive after undergoing external beam radiation therapy. The radiation only lasts for a few moments as it acts on the cancer cells. It is safe to be around people after treatment.
Brachytherapy, which involves implanting a radioactive device in the body, can make you radioactive for a period of time. If you undergo this type of therapy, your medical team will explain what happens and the necessary safety precautions.
External beam radiation is an important part of a multi-modal treatment for mesothelioma. It can cause side effects, but more advanced radiation strategies lower risks. For someone with mesothelioma, radiation may be crucial for extending life after surgery. Radiation therapy can also help keep patients living with cancer more comfortable.
