External Beam Radiation Therapy

Radiation therapy, or radiotherapy, is one of three main mesothelioma treatment types. To maximize treatment effectiveness, radiation therapy is often done in combination with chemotherapy, surgery, or both. Radiation therapy involves high energy particles capable of killing cancer cells. The most common way to deliver this treatment is external beam radiation. In this method, a beam of radiation is aimed at the tumor from outside the body. There are risks associated with radiation therapy. However, advances in research have made the technique safer and more focused.

Types of Radiation Therapy

Radiation therapy works 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. Also, because it damages healthy tissue, radiation therapy has a number of side effects.

External beam radiation is one main type of radiation therapy. This method uses external radiation aimed at the part of the body that contains the tumor. A machine, usually a linear accelerator, produces X-rays or another type of high-energy radiation, focuses it into a beam, and aims it at the correct spot on a cancer patient’s body.

Another type of radiation therapy is brachytherapy. Brachytherapy uses a radiation-emitting device planted inside the patient’s body. The small brachytherapy 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.

Types of External Beam Radiation Therapy

There are several types of external beam radiation. Most techniques developed from recent advances allowing 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 shape of the tumor. This conformity results in less damage to healthy tissue.  Modulating radiation intensity improves precision even more.

Another type of external beam radiation utilizes proton beams rather than the photons of traditional radiation treatment. This method damages less healthy tissue than the traditional method.

Intraoperative radiation dosed to a patient during surgery.

Electromagnetic-guided radiation uses small transponders implanted in the body to guide radiation to the tumor.

External Radiation Therapy for Mesothelioma

External radiation therapy is the most common type used to treat cancers, including mesothelioma. It is either used after surgery or for palliative care. After surgery, radiation is used to destroy 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 single cancer cell. Radiation after surgery can effectively “clean up” the area, killing any remaining cancer cells. This method extends life expectancy in patients who have undergone an extrapleural pneumonectomy.

Radiation treatment is also important for palliative care. When a cure is no longer possible, palliative treatments are used to make the patient more comfortable. External beam radiation can shrink tumors. As a result patients may breathe easier or experience a reduction in pain and swelling.

What to Expect

If you undergo external beam radiation therapy, you can expect several steps. The first step involves an examination by a radiation oncologist. Next, you will probably need imaging scans. This could involve CT scans or MRIs, depending on the type of therapy your doctor intends.

Your skin may be marked with ink to help technicians aim the radiation beam. You may also be fitted to body molds to help you stay in the correct position during the treatment. These molds also help guide the radiation beam. During the actual treatment, you will be guided to the correct position and put into the molds. Then the technician or doctor will 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 15 to 30 minutes.  You may have several such sessions on different days.

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, minimize 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.

Commonly, patients undergoing radiation will experience a loss of energy. 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, which may be permanent or last several months. For peritoneal mesothelioma, radiation to the abdomen can harm the bowels or bladder, which may lead to digestive issues or incontinence. Rarely, radiation therapy leads to a secondary cancer.

External beam radiation is an important part of a multi-modal treatment for mesothelioma. It can cause side effects. However, 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.