If you are diagnosed with pleural mesothelioma, you may receive radiation treatments for the disease. Radiation is part of the tri-modal process of treating this type of cancer, along with surgery and chemotherapy.
Understanding Mesothelioma Radiation
While it was initially felt that radiation wasn’t appropriate for the management of mesothelioma, it has been since discovered that radiation therapy can prolong the life of a person with this disease.
The main goal of radiation therapy for mesothelioma is to relieve pain; however, radiation also has the ability to kill remaining cancer cells.
Radiation for mesothelioma can be of different types. For pleural mesothelioma, the radiologist will likely give you external ionizing radiation directed toward the area of the tumor. Radiation isn’t painful and can actually relieve pain. It also works by killing off the mesothelioma cancer cells, as the radiation damages the DNA inside the cells so they can no longer survive and replicate.
People with pleural mesothelioma often have chest wall pain from the tumor invading the chest wall. Radiation treatments can shrink the tumorous areas so that pain can be relieved. Radiation is often done after having surgery to get rid of the bulk of the tumor mass.
Purposes of Radiation Therapy in Mesothelioma
There are three major reasons why radiation might be used in the treatment of mesothelioma, including:
- Adjuvant Therapy after Surgery. Radiation can be given after the patient has surgery and it can be done regardless of the type of surgery you have for your mesothelioma. In an extrapleural pneumonectomy, one lung is removed entirely and radiation is directed at the area where the lung used to be, sparing radiation exposure to the healthy lung. In a pleurectomy with decortication procedure, the radiation is precisely delivered to the area where the cancer used to be, but tries to avoid damaging the lung that was spared during the procedure. Research has shown that radiation therapy after surgery can more than double your survival time.
- Palliative Relief of Pain. Radiation has the capacity to relieve cancer pain when the cancer has spread to the lymph nodes of the chest, or to the chest wall itself. About half of all people who had symptoms of pain and shortness of breath after cancer surgery will have a decrease in these symptoms after receiving radiation treatments to the tumor site. Radiation can be done any time after surgery if pain arises from recurrence of the tumor.
- Prevention of seeding. Mesothelioma is a type of cancer that spreads along surgical incisions, biopsy sites, and sites where thoracentesis has been done. This is also called seeding of the cancer, which means that the cancer has spread. Up to half of all patients will have seeding after having one of the above procedures. Researchers have discovered that, if the site of these procedures are irradiated afterward, the chances of seeding to incision sites is decreased. This is still a little bit controversial, as some studies have not shown an effectiveness of radiation in the prevention of seeding. If seeding does occur, however, radiation can shrink the nodules that develop as a result of the seeding process, which can decrease the pain of these nodules.
Types of Radiation
There are two different types of radiation therapy used in the management of pleural mesothelioma. These include the following:
Brachytherapy
This is the least used type of radiation for management of pleural mesothelioma, but it is still used in some situations. Brachytherapy involves making an object (such as beads) radioactive and inserting the radioactive substance directly where the tumor used to be. The local radiation acts on the tissues it is embedded in, killing off mesothelioma cells that weren’t fully removed during surgery. This has the advantage of not causing radiation exposure to healthy tissue and only affects the immediate area where the radiated substance has been used.
Brachytherapy can be a permanent or just a temporary use. The beads are generally radioactive for several months. The beads can be removed after their radiation has been spent, or they could be allowed to remain in the body after they are no longer radioactive. Most mesothelioma doctors leave the beads in the body as they rarely cause pain. In order to do the brachytherapy, the doctor can put the beads in at the time of surgery or they can insert the beads using a large needle and imaging techniques to properly direct the beads where the tumor used to be.
Some doctors prefer to use high dose surface brachytherapy. In this procedure, the radioactive object isn’t used inside the body but is instead placed upon the skin at the incision site. This can prevent seeding of tumor into the incision itself. As it is just attached to the skin, it can be easily removed once the radiation has been spent.
If the brachytherapy is intended to be permanent, the beads are inserted near the tumor site and the patient goes home the same day. Because the dose of radiation is small, it does not affect other people and only works in the immediate area where the cancer was located. This is a palliative procedure, meaning it is intended to increase the patient’s comfort but does not cure the disease.
External-beam Radiation Treatments
In this procedure, a machine that generates radiation is directed at any site that is involved in the tumor. This is done on an outpatient basis and is often done more than once. It isn’t painful to have this type of treatment; however, it can irritate the skin and lead to minor burns. Markers are tattooed on the body where the surgeon wants the radiation to be given so that the doses of radiation can be administered at the same site each time the radiation machine is used. These markers last for a long time and, in some cases, are permanent. Radiation therapy is usually given once daily, 5 times a week for several weeks in a row. It means the patient must go to the hospital for an hour each day in order to receive the therapy for that day.
External beam radiation comes in two types. There is three-dimensional conformal radiation therapy, in which 3-dimensional images are taken of the tumor and a uniform intensity of radiation is delivered to the site. There is also intensity-modulated radiation therapy, in which different intensities of radiation are delivered in the specified area. More radiation is given directly at the tumor site and less radiation is given to the surrounding area.
Getting Radiation Treatments
When you receive radiation, the first step is to define the area to be irradiated. This is usually done by having an MRI or CT scan of the affected area and marking the area to be treated. The doctor may prescribe medications that increase the effectiveness of the radiation or medications to prevent damage to the normal cells in the radiation field.
When the radiation is underway, you can develop skin burns or blistering and moderate fatigue. Years later, there can be scar tissue in the lung that can be painful or result in shortness of breath. You can also have destruction or calcification of local lymph nodes where the site was irradiated.
Other side effects of radiation treatments include radiation pneumonitis, radiation myelitis, nausea, hair loss, skin burns, damage to the liver or heart, pleural effusion, fatigue or esophagitis. Not everyone will have adverse reactions to radiation therapy, and it can be very helpful in controlling the symptoms of mesothelioma.