Radiation therapy is very effective for pain and other cancer-related problems, such as bleeding from the lung or bladder, in some cancers that are too advanced to be cured. For example, pain in the bones caused by cancer spread can be significantly reduced or eliminated in approximately 75% of patients.
|How effective is radiation therapy for cancer|
What is Radiation Therapy?
Radiation therapy is a type of cancer treatment in which high-energy x-rays or other particles are used to destroy cancer cells. A radiation oncologist is a doctor who specializes in the use of radiation therapy to treat cancer. A radiation therapy regimen, or schedule, typically consists of a predetermined number of treatments administered over a predetermined time period.
Radiation therapy can be used to treat a wide range of cancers. It can also be combined with other cancer treatments like chemotherapy and/or surgery.
This article provides a general overview of radiation therapy, its various types, and why it is used to treat cancer. Learn more about what to expect during radiation therapy and the potential side effects.
How does radiation therapy treat cancer?
Cancer begins when healthy cells change and proliferate uncontrollably. Every cell in the body goes through a cycle of growth, division, and multiplication. Cancer cells progress through this process more quickly than normal cells. Radiation therapy causes DNA damage in cells, causing them to stop growing or to be destroyed.
In contrast to other cancer treatments that affect the entire body, such as chemotherapy, radiation therapy is typically a local treatment. This means that it usually only affects the area of the body where the cancer is located. Some healthy tissue near the cancer cells may be damaged during treatment, but it usually heals after the procedure is completed.
There are numerous types of radiation therapy, each of which works slightly differently to destroy cancer cells.
What are the goals of radiation therapy?
The goals of radiation therapy are determined by the type of cancer you have and how far it has spread. Radiation therapy can be administered alone or as part of a multi-modal treatment plan. Radiation therapy is used in a variety of ways, including:
- As the primary therapy. The goal of radiation therapy is frequently to eradicate all cancer and prevent it from returning.
- Prior to any other treatments. To shrink a large tumor, radiation therapy can be used before other treatments such as surgery. This is referred to as "neoadjuvant radiation therapy."
- After other treatments. Radiation therapy can be used after other treatments to eliminate any remaining cancer cells. This is referred to as "adjuvant radiation therapy."
- To relieve symptoms. Radiation therapy can be used to alleviate the symptoms of cancer. This is referred to as "palliative radiation therapy."
Radiation therapy can be used to treat a wide range of cancers. More than half of cancer patients will receive some form of radiation therapy. Radiation therapy alone is an effective treatment for some cancers. Other cancers benefit from a combination of treatments. Recurrent and metastatic cancer can also be treated with radiation therapy. Cancer that recurs after treatment is referred to as recurrent cancer. Cancer that has spread to other parts of the body is known as metastatic cancer.
What are the different kinds of external-beam radiation therapy?
External-beam radiation therapy is the most common type of radiation therapy. It emits radiation from a machine located outside the body. If necessary, it can be used to treat large areas of the body.
The radiation beam for x-ray or photon radiation therapy is created by a machine known as a linear accelerator or linac. The beam's size and shape are adjusted using special computer software. This allows the tumor to be targeted while avoiding healthy tissue nearby.
The majority of radiation therapy treatments are administered every weekday for several weeks. To help people stay still and ensure that the beam reaches the same area each session, form-fitting supports or a plastic mesh mask are used for radiation therapy to the head, neck, or brain.
External-beam radiation therapy is classified into the following types:
- Three-dimensional conformal radiation therapy (3D-CRT). Detailed 3-dimensional images of the cancer are created using computed tomography (CT) or magnetic resonance imaging (MRI) scans during this type of radiation therapy. These images are used by the treatment team to direct the beam. This technique allows the treatment team to safely use higher doses of radiation therapy while minimizing damage to healthy tissue. This reduces the possibility of side effects.
- Intensity-modulated radiation therapy (IMRT). This is a more advanced type of radiation therapy. The intensity of the radiation is varied with IMRT. This differs from traditional 3D-CRT, which uses the same intensity for each beam. IMRT targets the tumor while avoiding healthy tissue more effectively than conventional 3D-CRT.
- Proton beam therapy. Instead of x-rays, protons are used in this treatment. A positively charged particle is a proton. Protons with high energy can destroy cancer cells. Protons are delivered to the tumor and deposit a specific dose of radiation therapy. In contrast to x-ray beams, proton therapy delivers very little radiation dose beyond the tumor. This minimizes the damage to nearby tissue. Proton therapy is a relatively new treatment that necessitates the use of specialized equipment. Currently, it is only used to treat certain types of cancer. Find out more about proton therapy.
- Image-guided radiation therapy (IGRT). Imaging is used during radiation treatment in IGRT. Images are taken immediately before and during treatment and compared to imaging taken prior to treatment. This allows doctors to precise position the radiation.
- Stereotactic radiation therapy (SRT). This treatment targets a small tumor area with a large, precise dose. The patient must maintain complete stillness. Individual body molds or a head frame can help limit movement. SRT is frequently administered as a single treatment or in fewer than ten treatments. Some patients may require more than one course of SRT.
What is internal radiation therapy?
Brachytherapy is another term for internal radiation therapy. This type of radiation therapy involves injecting radioactive material into cancer or surrounding tissue. Permanent or temporary implants are available. A hospital stay may be required for this treatment.
Internal radiation therapy comes in a variety of forms, including:
- Permanent implants. These are small steel seeds containing radioactive material. The capsules are roughly the size of a rice grain. They provide the majority of the radiation therapy in the vicinity of the implant. Some radiation may, however, escape from the patient's body. This necessitates the implementation of safeguards to protect others from radiation exposure. The implants lose their radioactivity over time. The body retains the inactive seeds.
- Temporary internal radiation therapy. This type of radiation therapy can be administered using a needle, a catheter, or special applicators. The radiation can stay in the body for several minutes to several days. Internal radiation therapy is typically administered for only a few minutes to most people. Internal radiation therapy can sometimes be given for a longer period of time.
What other radiation therapy treatment options are available?
Other treatment options for radiation therapy include:
- Intraoperative radiation therapy (IORT). This treatment uses either external-beam or internal-beam radiation therapy to deliver radiation therapy to the tumor during surgery. IORT allows surgeons to move healthy tissue out of the way so that radiation therapy does not damage it. When vital organs are close to the tumor, this treatment is beneficial.
- Systemic radiation therapy. Patients are given a radioactive substance to swallow or an injection that targets cancer cells. The radioactive material is expelled from the body via urine, saliva, and sweat. These fluids are radioactive, and anyone who comes into contact with the patient should take the precautions recommended by the medical team (see below). Radioactive iodine therapy (RAI; I-131) for thyroid cancer is an example of systemic radiation therapy.
- Radioimmunotherapy. Systemic therapy is used in this case. Monoclonal antibodies, which are proteins that are attracted to very specific markers on the outside of cancer cells, are used specifically to deliver radiation directly to tumors. Because the treatment employs these specialized antibodies, the treatment has a lower impact on surrounding normal tissue. Ibritumomab (Zevalin), for example, is used to treat certain lymphomas.
- Radioprotectors and radiosensitizers. Radiosensitizers and radioprotectors are being researched by scientists. Radiosensitizers are substances that help radiation therapy destroy tumors more effectively. Radioprotectors are substances that protect healthy tissues in the vicinity of the treatment site. Fluorouracil (5-FU, Adrucil) and cisplatin are two examples of radiosensitizers (Platinol). Radioprotectors include amifostine (Ethyol).
Is radiation therapy safe for patients and their families?
For more than a century, doctors have used radiation therapy to treat cancer in a safe and effective manner.
Radiation therapy, like other cancer treatments, has side effects. Discuss with your medical team what to expect and how you are feeling during and after your treatment. While most people experience no pain during treatment, the effects of treatment accumulate over time and may include discomfort, skin changes, or other side effects, depending on where in the body treatment is administered.
Radiation therapy increases the risk of developing second cancer later in life by a small amount. However, for many people, radiation therapy cures their cancer. This benefit outweighs the minor risk that the treatment will cause new cancer in the future.
The patient does not emit any radiation after treatment sessions when receiving external-beam radiation therapy. Radiation is still present in the treatment room.
Internal radiation therapy, on the other hand, causes the patient to emit radiation. As a result, unless otherwise directed by the patient's doctor, visitors should adhere to the following safety precautions:
- If you are pregnant or under the age of 18, do not visit the patient.
- Keep at least 6 feet away from the patient's bed.
- Each day, limit your stay to 30 minutes or less.
- After using the restroom, thoroughly wash your hands.
- Separate utensils and towels should be used.
- Drink plenty of fluids to flush the body of any remaining radioactive material.
- Stay away from sexual activity.
- Avoid contact with infants, children, and pregnant women.