Radiation

Radiation therapy is a localized treatment used to directly kill cancer cells, lessening symptoms or directly fighting the disease.

Key Points

  • 1

    Radiation therapy is a common treatment for many cancers, including mesothelioma

  • 2

    Patients can be prescribed different kinds of radiation depending on the type of mesothelioma they have

  • 3

    Radiation therapy can span over weeks, days, or months

  • 4

    The biggest risk of radiation is damaging healthy tissue, which can lead to various side effects

Radiation therapy is one of the oldest and most frequently prescribed treatments for a variety of cancers, including mesothelioma. The American Cancer Society reports that about 60% of all cancer patients receive some form of radiation therapy. Somewhat less frightening than chemotherapy and surgery, radiation may be prescribed for the treatment of the disease itself or to help lessen the troublesome symptoms of cancer.

How Does Radiation Therapy Work?

High-dose radiation kills cancerous cells that are found in the body of a person suffering from cancer. Technically, the radiation destroys cancer cells at the molecular level and keeps them from reproducing. It is especially adept at killing cells that replicate quickly, such as those associated with mesothelioma.

A team of specialists including a radiation oncologist, medical physicists, and other healthcare providers will create a treatment plan and conduct radiation therapy. The team will carefully review x-rays, CT scans, and MRI studies to view the mesothelioma as it is situated next to healthy tissue. These radiological images will be used to make precise measurements, and the team will identify the best dose of radiation for the given patient.

Several issues are considered during radiation therapy. The medical professionals will attempt to avoid directing the beam at healthy tissues that surround the tumor, but will calculate a radiation dose that should be toxic to the entire diseased area. Since mesothelioma rarely forms a discrete tumor and grows near many sensitive areas (e.g., the spinal cord, heart, esophagus, liver, and opposite lung), every effort is made to direct the beam at the cancer cells and limit damage to healthy tissues. Specialized radiation delivery techniques have been developed to more precisely target mesothelioma cells.

Unlike chemotherapy, however, mesothelioma radiation therapy is a localized treatment which kills only the cells in the area to which the radiation is applied. It is not helpful in treating cancer which has metastasized – or spread to other parts of the body.

Radiation and Mesothelioma

Some mesothelioma patients are not candidates for radiation therapy, while the treatment may be, in fact, preferable for others. It also may be offered in tandem with other treatments, like surgery or chemotherapy.

While radiation therapy will not cure mesothelioma, doctors often suggest it as a palliative measure in order to relieve some of the uncomfortable side effects of the disease. Radiation therapy has proven quite successful in relieving pain as well as reducing instances of shortness of breath in mesothelioma patients.

Oncologists experienced in the treatment of mesothelioma will be able to determine if and how you might benefit from radiation therapy. If it is prescribed for you or a loved one, it is essential to stick to the schedule so that the patient receives the most benefit from the treatment.

Types of Radiation Therapy

Traditionally, there have been two types of radiation therapy available to cancer patients, external beam radiation and internal radiation. However, there are several other types of radiation therapy that may be available for patients depending on the type of mesothelioma they have.

External Beam Radiation

The most common form of radiation therapy, external beam radiation is achieved by means of an x-ray machine which aims radioactive waves at the tumor or affected portion of the body. Positioning of the radiation delivery device is critical. During the first treatment, a small tattooed dot (the size of a freckle) or semi-permanent ink dots may be applied to the skin to mark a location for the current and subsequent radiation treatments. A precise dose of radiation is delivered by a radiation beam to the tumor. Since the beam is outside of the body, healthy tissue such as skin, muscle, and bone may receive some radiation as well.

The procedure is fairly quick and is accomplished on an outpatient basis. The actual exposure to radiation takes a few minutes, but the positioning and preparation may take 20 minutes or more. How many radiation treatments a patient requires will depend on individual cases and include factors such as stage of the disease and size and location of the tumor, but the standard is administered five days a week over the course of several weeks.

Internal radiation

Also known as brachytherapy, this type of radiation involves placing a radioactive implant into the cancerous tissue. It allows for the implementation of higher doses in a single treatment or is suggested for patients with tumors that are located deep inside the body and are unable to be reached by traditional external beam radiation. Brachytherapy is considered a highly targeted form of radiation. Patients must be admitted to the hospital for internal radiation, and because exposure to the patient may cause danger to others due to radioactivity, visitors will be limited for the first few days. Implants such as these may be temporary or permanent, and can be offered as a first course of treatment, paired with chemotherapy or used after surgery.

Temporary BrachytherapyPermanent Brachytherapy
  • Can be low or high dosage
  • Radioactive material placed near tumor
  • Inserted for predetermined amount of time then removed
  • Radioactive seeds or pellets implanted near tumor
  • Radioactive for weeks or months, dependent on dosage
  • Left in permanently

3D-CRT

3D-CRT stands for three-dimensional conformal radiation therapy. 3D-CRT is a form of external radiation that matches the radiation beam to the shape of the tumor. In traditional external beam radiation therapy, treatment is provided based on a two-dimensional representation of the body. In 3D-CRT, specialized software is used to convert two-dimensional images into a three-dimensional representation of the body and the tumor. Therefore, the radiation treatment specialists can direct the radiation to the tumor in three-dimensional space. The result of this process is that more radiation is delivered to the tumor and less radiation is delivered to healthy tissue.

Like traditional external beam radiation, the 3D-CRT treatment is painless. Since targeting in 3D-CRT is more precise than in the traditional approach, higher doses of radiation can be used. Thus, the cancer-killing potential of the treatment is higher.

IMRT

IMRT stands for Intensity Modulated Radiation Therapy. Like 3D-CRT, IMRT delivers radiation precisely to areas with tumors while mostly sparing surrounding tissue. Unlike 3D-CRT, IMRT delivers different intensities of radiation to the tumor. For example, a high-intensity beam can be directed at areas of large, solid tumor mass while lower intensity energy can be directed at thinner or smaller collections of cancer cells. Because of this enhanced precision, very high doses of ionizing radiation can be used with IMRT.

IMRT may be more effective than external beam radiation therapy and may cause fewer side effects. When IMRT is compared to 3D-CRT, however, the differences in effectiveness are less impressive. IMRT is able to deliver higher amounts of radiation to the mesothelioma, but it still puts healthy organs at risk.

Recently, enhancements have been made to IMRT that may make it even safer. When IMRT is delivered with a technology called helical tomotherapy, high-dose radiation can be delivered more precisely to cancer cells and relatively little strikes healthy tissue. Just as computed tomography (CT) takes X-ray images in “slices,” helical tomotherapy delivers radiation therapy in horizontal “slices” of the body. The intensity of the beam changes with the size of the tumor in each slice. The result is an even higher level of precision than typical IMRT treatments.

Intraoperative Radiation

Intraoperative radiation is the application of ionizing radiation to tumor cells during the course of surgery. The theoretical advantage of intraoperative radiation is that the beam of radiation can be directed on the tumor itself rather than first traveling through healthy tissue. Another possible advantage of intraoperative radiation is the radiation will kill all mesothelioma cells within the chest cavity since, during surgery, the treating physician can see the tumor directly.

Unfortunately, intraoperative radiation has not shown much success. One research group deemed the treatment “prohibitively toxic” and reported serious complications when intraoperative radiation was combined with extrapleural pneumonectomy. It is not known whether intraoperative radiation is beneficial when combined with pleurectomy and decortication, however.

What to Expect During Radiation Therapy

Once your doctor has determined that you are a candidate for external radiation therapy, he/she will suggest an outpatient facility where you can receive the treatment. If internal radiation therapy is in order, you may be sent to a consult with a surgeon before you receive the treatment. He/she will set up a schedule of treatments as well. The schedule may involve days, weeks, or even months of radiation therapy.

While you will experience some side effects from surgery after brachytherapy as well as some traditional radiation therapy side effects, the side effects of external radiation are quite mild compared to most other cancer therapies. The downside of radiation is that it can also destroy healthy cells along with cancerous cells. However, these cells will eventually begin to repair themselves.

Side Effects of Radiation Therapy

The biggest risk associated with radiation therapy is the potential for healthy tissue to be damaged, which could result in a number of side effects.The most common side effects of radiation therapy will vary depending on the type of mesothelioma, and hence the location of the body receiving treatment. These side effects may worsen or last longer if radiation therapy is combined with chemotherapy. Some of the common side effects are:

  • Extreme fatigue
  • Redness near the treated area
  • Nausea
  • Vomiting
  • Dry mouth
  • Loss of appetite
  • Diarrhea
  • Hair loss (infrequent)
  • Decrease in white blood cells (leaving patient prone to infection)

Patients will face different side effects, so it’s important to discuss what you are experiencing with your healthcare team. Your doctor may be able to recommend lifestyle, dietary or treatment changes to better manage these effects.

Factors That Impact A Patient’s Risk of Experiencing Side Effects

Whether or not a patient experiences side effects depends on a variety of factors, including:

  • Overall Health
  • Dose of radiation, daily and total
  • Location of treatment on the body
  • Genetics
  • Other treatments such as chemotherapy
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