One of the most common forms of treatment after a mesothelioma diagnosis is radiation therapy. There are many benefits to utilizing this method of treatment, but it is also important as a patient to understand what you should expect during and after the use of this therapy. Your medical team can provide additional information about radiation and other forms of treatment to help develop the best course of treatment for your case.
What is Radiation Therapy?
Radiation therapy uses high-energy X-rays and other energy particles to kill mesothelioma cancer cells. Certain types of cells, such as cancer cells, have a greater sensitivity to high-energy radiation than normal cells due to their rapid growth and limited ability to repair the damage, which is why radiation is often used as a treatment method. The eligibility of patients for this type of treatment for mesothelioma is based on the stage of their diagnosis, the patient’s overall health, and the location of the tumor. There are two main types of radiation therapy that may be used to treat mesothelioma:
External beam radiation therapy (EBRT)
External beam radiation therapy is a non-invasive treatment that uses high-energy X-Rays aimed directly at cancer cells and tumors. There are many forms of EBRT, with the most common being intensity-modulated radiation therapy. This method allows for the radiation photons to vary in strength, allowing it to more precisely target tumors and minimize the damage to surrounding areas. Intensity-modulated radiation therapy is an advanced version of 3D conformal radiation, which confirms a three-dimensional rendering of the tumor and emits radiation in multiple doses. There is also a 4D version of EBRT known as image-guided radiation therapy that offers radiation treatment and a CT scanner in a single machine. This allows the patient to remain in a single machine while receiving both imaging and treatment of radiation therapy.
Proton therapy is another form of external beam radiation therapy, which uses a different type of energy to deliver treatment to mesothelioma tumors. Protons release energy at a certain point, as opposed to photons that release energy throughout, which allows for more precise delivery of radiation to affected areas. EBRT in any form is fast and painless during the treatment itself, but the setup time to get the patient in the correct position for treatment can take longer depending on the site of the tumor.
One new way that radiation is being used is through Surgery for Mesothelioma After Radiation Therapy (SMART). In this process, higher than normal doses of radiation are given at the site of a tumor that has been marked for surgical removal in an effort to shrink the tumor as much as possible prior to surgery. The higher dose also reduces the chances that mesothelioma cells will be left behind after treatment. The surgery typically takes place one to two weeks after the radiation therapy ends. This treatment option with radiation is still undergoing study, but the results thus far have been promising. A related treatment process, Surgery for Mesothelioma After Radiation Therapy Using Extensive Pleural Resection (SMARTER), is also being tested that utilizes a similar process but removes a larger amount of tissue during surgery.
The second type of radiation treatment is known as brachytherapy. This type of radiation kills mesothelioma cells by implanting radioactive material inside the patient at the source of the disease. There are a couple of different methods that doctors use when utilizing brachytherapy. The first is to place the radioactive material in the tumor during surgery as part of a multimodal treatment plan. The second option is to use a tube to implant the material with the help of an imaging scan. Over time, the radiation emitted from the implanted material kills the cancer cells around it, but it may also affect other healthy cells within the radioactive radius.
Purposes of Radiation Treatment
Radiation therapy serves two main purposes. The first purpose of radiation treatment is curative, which means that the ultimate goal of radiation is to cure the mesothelioma tumor and get the patient into remission of their cancer. When radiation is used for this purpose, it is often done in conjunction with other forms of treatment like surgery, immunotherapy, or chemotherapy to fully eradicate all traces of the mesothelioma cancer cells. Typically, radiation is done as one of the last elements of a curative multimodal plan to eliminate any remaining traces of cancerous cells that the other treatment methods may not have caught.
The second purpose of radiation therapy is palliative, which means that it is used to reduce the symptoms of mesothelioma and improve the quality of life of the patient. Because radiation therapy often reduces the size of an existing mesothelioma tumor it can reduce the pain caused and other symptoms of cancer as part of palliative care. It is important to note that radiation can be used simultaneously as curative and palliative treatment, with the benefits of palliative care while simultaneously attempting to eradicate cancer completely for curative purposes.
Whether for curative or palliative care, there are many goals for radiation therapy. Utilizing this method can shrink tumors prior to surgery, which makes them easier to remove. Radiation can also prevent cancer cells from spreading to new areas of the body during surgery as well as kill off any remaining mesothelioma cells after surgery is complete. Finally, radiation has the power to shrink tumor size to reduce the pain that mesothelioma patients feel, regardless of whether the tumor is operable or not.
Benefits of Radiation Therapy as Treatment
Whether using radiation therapy for curative or palliative treatment, there are multiple benefits for including radiation as part of a treatment plan with your medical team. The first benefit of radiation is an improved survival rate. Radiation increases the average survival rate of mesothelioma patients because it reduces the chances of a local recurrence of the mesothelioma cancer cells. Depending on the type of mesothelioma and overall treatment plan, patients have lived three to five years longer when utilizing radiation therapy.
Another benefit to radiation treatment is pain relief. This is one of the main purposes of radiation therapy as a palliative form of care, as radiation can reduce the size of existing mesothelioma tumors. Even if the tumor is inoperable given its size, location, or the stage of diagnosis, reducing the size of a mesothelioma tumor can reduce the pressure on internal organs like the lungs, abdominal organs, chest, or spine. Well over half of all mesothelioma patients that utilize radiation therapy report reduction in pain after treatment.
A third benefit of radiation therapy is seeding prevention. One of the downsides of surgery as a treatment option for mesothelioma is that during the incision microscopic cancer cells can be moved to new areas, which is also known as seeding. Some treatment plans will use radiation along the site of the incision to kill any microscopic cancer cells and prevent seeding from occurring.
Side Effects of Radiation Therapy
No treatment for mesothelioma comes without side effects, and that also applies to radiation therapy. Thankfully, the side effects of radiation treatment are often less severe than those for other types of mesothelioma treatment, such as chemotherapy. Many of the side effects for radiation are temporary, but some patients have reported chronic side effects in the months and years following radiation therapy. Some of the most common side effects of radiation therapy include the following:
- Skin irritation,
- Hair loss in the treatment area,
- Difficulty swallowing,
- Shortness of breath,
- Fullness of the chest (radiation pneumonitis), and
- Scarring (radiation fibrosis)
The skin irritation happens mostly at the site of the radiation treatment, also known as radiodermatitis, and can present in many forms. The most common are as rashes, redness, swelling, or a tight feeling on the skin. The skin may also darken or peel at the site of the radiation therapy. Any fatigue associated with radiation therapy typically peaks two to four hours after a therapy session is complete and has been noted to be the most severe later in treatment cycles as the healing process usually takes up a greater amount of the patient’s energy.
The side effects of radiation treatment can also vary by the type of mesothelioma diagnosed by the medical team. For pleural mesothelioma, which affects the lining of the lungs, radiation can temporarily intensify the existing symptoms of mesothelioma before reducing them, such as shortness of breath, difficulty swallowing, or coughing. In rare cases, the lungs could actually become scarred from radiation treatment, which is known as radiation fibrosis. Chest radiation can also cause inflammation in some cases, known as radiation pneumonitis, and in very rare instances it can cause fluid buildup, collapsed lungs, and calcification of the lymph nodes.
Peritoneal mesothelioma, which affects the lining of the abdomen, can also benefit from radiation but not to the same level as pleural mesothelioma because of the toxicity of radiation energy to the abdominal organs. A small amount of radiation can affect the small intestine, liver, kidneys, and other abdominal organs and cause nausea, vomiting, and inflammation of these organs. Typically, radiation therapy is reserved only to prevent seeding with surgery for peritoneal mesothelioma. It is also not recommended for pericardial mesothelioma when the cancer is caught pre-mortem because the energy from radiation treatment can be damaging to the heart.
How Does the Process Work?
There are many steps to the radiation treatment process when a patient opts for this form of therapy for curative or palliative purposes. The first step is the initial appointment, which is a consultation visit. The radiation oncologist will explain the process, the potential side effects, and they may have you sign forms agreeing to treatment. At this initial visit you will also determine how many sessions are appropriate for the first cycle and whether the oncologist believes that additional cycles of treatment will be needed for your specific mesothelioma care. Also known as marking sessions, the initial appointment may also include setting up pillows or body molds to help the patient hold the correct position for when treatment does occur.
The second step in the process for radiation treatment is an imaging scan. This is usually done with a CT scan, which determines the exact size, shape, and location of the mesothelioma tumors identified for treatment. This allows the oncologist to apply radiation precisely at the tumor site and minimize damage to the surrounding tissues. Depending on the number of sessions and progression of treatment, additional imaging scans may be taken during radiation treatment to ensure that the therapy is continuing to target cancerous cells. This step may also be done in conjunction with treatment if image-guided radiation therapy is utilized.
The third step in the process for radiation is the treatment itself. The patient arrives at the treatment location, where medical staff will help them prepare. They position the patient and apply protective coverings to areas of the body not being treated. The patient must lie in the machine as still as possible during treatment so that the radiation hits the correct location. A radiologist technician will be present at all sessions to ensure that the machine is working properly and that the patient is not feeling any discomfort during the session. The treatment itself is fast and only last a few minutes, typically between ten to thirty minutes. Generally, radiation treatment occurs one or more times per week for several weeks, which is also referred to as a cycle of treatment.
The final step in the process is the follow-up appointment. These occur throughout treatment as well as after a cycle of radiation therapy has ended. The oncologist will ask about the extent and severity of side effects and may alter treatment based on the response. After a cycle, the follow up appointment may include additional scans to see how the radiation has impacted the size of the mesothelioma tumors and to determine whether additional cycles of radiation therapy would be beneficial for care.
Recovery from radiation therapy, both during treatment and afterward, is also an important step in the process. Because the side effects of radiation treatment are often less intense than surgery or chemotherapy, some mesothelioma patients continue to work and live life as normally as possible during radiation treatment. However, if fatigue and other side effects increase in severity throughout the course of a cycle, a patient may need more time to recover in between treatments, which in turn could affect their day-to-day life. If recovery does take longer, the patient should discuss this with their oncologist as well as other members of their care team to determine if there are any other palliative options to help minimize the side effects of radiation treatment.
Survival Rates with Radiation Treatment
As noted earlier, the survival rates of mesothelioma patients are based on a number of factors, and including radiation therapy as part of the treatment plan can improve the survival rate of a patient if it is recommended as part of a multimodal plan. Some of the factors that impact the survival rate of a patient with mesothelioma include the mesothelioma cell type, the patient’s overall health, the stage of diagnosis, the type of mesothelioma detected, and the type of radiation therapy utilized for treatment. When utilized as part of a multimodal plan, survival rates have increased as follows:
- Pleural mesothelioma: Median survival – 39.4 months with chemotherapy, surgery, and radiation therapy
- Peritoneal mesothelioma: Median survival – 8 months with surgery and radiation therapy
- Pericardial mesothelioma: Median survival – 50 months with surgery followed by intermittent chemotherapy and radiation
- Testicular mesothelioma: Median survival – up to 155 months with surgery and radiation