Radiation Therapy to Treat Cancer

Radiotherapy is one of several types of cancer treatments that use radiation to destroy tumor cells. Radiotherapy is often given alone or combined with surgery, chemotherapy, or hormone therapy.

The term “radiotherapy” refers to both external beam radiotherapy (EBRT), where the radiation source is outside the patient’s body, and brachytherapy, where the radiation source is placed directly into the area being treated. EBRT is usually performed using either conventional X-ray machines or linear accelerators. Brachytherapy is typically delivered using radioactive sources such as seeds, pellets, wires, or catheters.

How radiation therapy works against cancer

Cancer cells divide rapidly because they want to grow bigger and spread throughout the body. They do this by making copies of themselves, called mitosis. During each cell division, the genetic material inside the cell gets duplicated into daughter cells. This process is controlled by genes. If you damage some of those genes, it causes problems. For example, damaged genes might cause cells to make too many proteins, causing tumors. Or damaged genes could cause cells to lose control over how they grow and multiply, leading to uncontrolled cell growth, such as in cancers.

Radiation therapy uses ionizing radiation—high-energy particles like X-rays, gamma rays, protons and neutrons—to destroy tumor cells. Ionizing radiation damages DNA, which stops cancer cells from growing and multiplying. Cells that cannot reproduce, such as most normal tissue cells, are less likely to be affected by radiation.

The amount of radiation needed depends on where the cancerous cells are located within the body. In general, the lower the number of cells, the smaller the dose of radiation required. But sometimes, even small doses aren’t enough to cure a patient.

When radiation therapy is used to treat cancer, doctors give patients different amounts of radiation depending on what

Types of radiation therapy

There are two main types of radiotherapy: external beam and internal. External beam therapy uses beams of high energy x-rays or electrons directed to the area of treatment. This is usually done with machines that move around the patient during treatment. Internal radiotherapy delivers radioisotopes directly into the tumor – either by injection or implantation – rather than exposing healthy tissue to damaging rays. If the tumor is small enough, it may be possible to surgically place radioactive seeds inside the tumor itself.

External beam therapy requires special equipment, such as linear accelerators, that produce highly focused beams of radiation. These beams are often shaped like cones or cylinders to reach areas deep within the body. They travel along paths called tracks. In some cases, the track follows the shape of the tumor; in others, it travels around the tumor. A computer controls the machine to ensure that the correct dose reaches the target while sparing nearby organs.

Internal radiotherapy relies on isotopes that emit low levels of radiation over a long period of time. Isotopes used include iodine 131, strontium 90, yttrium 90, rhenium 186, palladium 103, cesium 137, iridium 192, samarium 153, phosphorus 32, platinum 197, gold 198, bismuth 213, and radon 222. Radioactive sources are placed near the tumor under ultrasound guidance.

Why people with cancer receive radiation therapy

Radiation therapy is used to treat many types of cancer, including breast, prostate, lung, head and neck, colon, rectal, uterine cervix, testicular, ovarian, brain, esophageal, stomach, liver, pancreas, thyroid, skin, lymphoma, leukemia, myeloma, Hodgkin’s disease, and sarcoma.

When used to treat cancer, it can cure cancer, prevent cancer from coming back, or stop or slow the growth of cancer cells.

External beam radiation may shrink tumors. Radiotherapy uses high energy x-rays or gamma rays to kill cancer cells directly. This treatment kills cancer cells without damaging normal tissue around the tumor.

Pain from cancer that has spread out of the original site can be treated with systemic radio-pharmacological agents. These drugs deliver radioactive material into the bloodstream where it travels to the bones and destroys the cancerous cells there.

Types of cancer that are treated with radiation therapy

External beam radiation therapy is used for treating many types of cancer. Brachytherapy is mostly used to treat cancers of head and neck, breast and cervical cancers. Radioactive iodine, or I- 131, is used to treat thyroid cancer. Targeted radionuclide therapies are used to treat some patients with advanced prostate cancer or GEP-NET. This type of treatment may be referred to as molecular radioimmunotherapy.

How radiation is used with other cancer treatments

Radiation therapy is one of several types of cancer treatments. Most people receive radiation therapy along with other forms of cancer care. This includes surgery to remove tumors; chemotherapy to kill tumor cells; and/or immunotherapy to boost the body’s immune system against cancer.

The timing of when radiation therapy begins depends on the type of treatment you are receiving. Radiation therapy may begin before, during, or immediately after surgery. In addition, some patients receive radiation therapy before starting chemotherapy or immunotherapy. And others start radiation therapy later in the course of cancer treatment.

When radiation is combined with surgery to remove tumors, it is usually given before surgery. Sometimes radiation therapy is given before surgery to shrink the size of a tumor so it can be easily removed by surgery. Radiation therapy is sometimes given before surgery to reduce the chance that the tumor will come back.

What are the goals of radiation therapy?

Radiation therapy is one of the most common treatments for cancer. In fact, over half of people diagnosed with cancer receive some form of radiation during their care. Radiation therapy uses high energy rays to kill tumor cells. These rays come from radioactive sources such as cobalt 60, cesium 137, iodine 131, radon 222, or X-rays. Some forms of radiation therapy use radioisotopes that emit particles called alpha particles, beta particles, gamma photons, neutrons, protons, or charged particles. Each type of particle has unique qualities that make it useful for particular kinds of tumors.

The goal of radiation therapy is to deliver enough energy to destroy cancerous tissue while minimizing damage to healthy tissues. This is done by carefully placing the radiation source near the tumor and directing the beams toward the tumor. The amount of radiation needed depends upon several factors including the size and location of the tumor, how far away the tumor is from vital organs, and whether the patient has been treated previously with chemotherapy or another form of radiation.

To cure or shrink early-stage cancer

Radiation plays a major role in treating many types of cancer. It kills cells by damaging DNA, including the genetic material inside each cell. When damaged DNA cannot repair itself, it leads to cell death. Cancer cells divide quickly, meaning there are always new cells ready to replace those killed by radiation. If you give enough radiation, eventually every single one of those new cells will die too.

In addition to killing cancer cells directly, radiation can kill nearby healthy tissue. This makes it important to use low doses of radiation, delivered over several weeks, rather than high doses delivered in just one session.

The goal of radiation therapy is to destroy cancerous tumors while minimizing damage to normal tissues. There are different ways to deliver radiation, depending on what type of cancer you’re trying to treat.

Types of beams used in radiation therapy

Radiation beams used in external radiation therapies come from three types of particle beams:

Photons are high energy electromagnetic waves. They are emitted during radioactive decay processes.

Protons are subatomic particles that carry positive charge. Protons are often accelerated in cyclotrons.

Electrons are charged elementary particles. Electrons are usually accelerated in linear accelerators.

Photons

Most radiation therapy machines use photons, which are high energy particles. They are also used in x rays, but x rays use lower doses. Photons can reach tumors deep in your body because they don’t stop once they hit the target; instead, they continue traveling deeper into the body. This makes them useful for treating cancers like prostate cancer.

As they travel through the body they scatter little bits of radiation off their path. This is why you feel the effects of radiation even though the treatment stops short of the tumor.

This is called collateral damage. Collateral damage occurs when healthy cells are damaged during the course of treatment. It can cause side effects such as nausea, vomiting, diarrhea, hair loss, fatigue, skin reactions, and problems with fertility.

Protons

Proton beam therapy uses protons—particles with a positive electrical charge—to kill cancer cells. Proton beams don’t spread out like X-rays, meaning they’re less likely to damage healthy tissues around the tumor. But they still deliver radiation dose precisely where it’s needed. They’re also expensive to build and maintain, and some doctors say they aren’t effective enough against certain kinds of cancers.

But researchers are working to make them more widely accessible. A team at Massachusetts General Hospital recently completed the world’s first clinical trial comparing proton beam therapy to traditional external-beam radiation. So far, the study found that both approaches work equally well at shrinking tumors and reducing side effects. And because proton beams are smaller and cheaper to produce than conventional ones, they could eventually become more common.

Electrons

The electron is one of the fundamental building blocks of matter. They are negatively charged subatomic particles that make up atoms. Electrons are found within every atom in our bodies. Their presence allows electrons to form chemical bonds.

A beam of electrons is used to diagnose medical conditions such as cancer. This treatment uses high energy X-rays to knock electrons out of tissue. These free electrons are collected into a beam and sent to a detector where they are captured. If there is no tumor present, the beam passes harmlessly through the patient. However, if there is a tumor, the beam stops in its tracks because it cannot pass through healthy tissue.

Types of external beam radiation therapy

External Beam Radiation Therapy

There are many different types of external beam radiation therapies. All of them share the goal of delivering high doses of radiation to tumors while minimizing damage to healthy tissues surrounding them.

The three main types of external beam radiation treatments are:

Intensity Modulated Radiotherapy (IMRT): This technique uses multiple beams of radiation aimed at the tumor from multiple angles. The intensity of each beam can be controlled individually to deliver the maximum amount of radiation to the tumor without causing too much harm to nearby organs.

Proton Beam Radiotherapy (PBRT): Proton beams use positively charged particles rather than X-rays to irradiate cancer cells. They travel very precisely along a specific path inside the body, delivering a concentrated dose of radiation directly to the tumor. PBRT works best for tumors located near critical structures such as nerves, blood vessels, and digestive tract.

Stereotactic Body Radiotherapy (SBRT): SBRT delivers a large number of small doses of radiation over short periods of time in order to kill cancer cells quickly. Unlike IMRT and PBRT, SBRT does not require moving parts like gantries or heavy equipment. Instead, a patient lies still during treatment, allowing doctors to target the tumor with pinpoint accuracy.

3-D conformal radiation therapy

What it is

3-dimensional conformal radiation therapy (3-DCRT) is a form of external beam radiotherapy that delivers precise doses of radiation to target tumors while minimizing damage to healthy tissue. This technique relies on computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) scans to accurately locate and characterize cancerous lesions within patients. These images are then analyzed by a radiation therapist, who designs the best possible radiation dose distribution based on the patient’s anatomy and disease characteristics.

The image-guided approach allows physicians to deliver precise radiation doses to malignant cells while sparing surrounding normal tissues. This approach minimizes side effects such as pain and swelling, and reduces the risk of developing long-term complications like fibrosis and necrosis.

3-DCRT is one of several types of external beam radiation therapies, including intensity modulated radiation therapy (IMRT), volumetric arc therapy (VMAT), stereotactic body radiation therapy (SBRT), proton therapy, and brachytherapy.

Risks

Radiation therapy side effects depend on where in the body it is administered and how much radiation is given. Side effects vary depending on what part of the body is being irradiated and how much radiation is delivered.

Common side effects include hair loss at the treatment site; skin irritation at the treatment site; fatigue; dry mouth, thickened saliva; difficulty swallowing; sore throat; changes in taste; nausea; mouth sores; tooth decay; chest pain; coughing, shortness of breath; abdominal cramps; diarrhea; pelvic pain; vaginal bleeding; urinary tract infection; blood clots; and erectile dysfunction.

Some side effects occur within weeks or months after treatment ends. They may continue for a few days or up to several months. Rarely, a second primary tumor (cancer developing in another area of the body) may develop years later. This type of secondary cancer occurs because some normal cells become damaged during treatment and continue dividing uncontrollably. These cells may form tumors in areas away from the original tumor.

Is radiation therapy safe for patients and their families?

Radiation therapy uses high energy particles called rays to kill tumors. Radiation therapy works well for some types of cancer, including breast, prostate, head and neck cancers, Hodgkin lymphoma, and others. In fact, it is one of the most effective ways to cure certain kinds of cancer. However, like other cancer treatments, radiation causes side effects. These side effects can affect different parts of the body and can vary from person to person.

Side effects of radiation therapy can include fatigue, nausea, mouth sores, hair loss, diarrhea, vomiting, constipation, dry eyes, headaches, difficulty sleeping, weight gain, numbness, tingling, sore throat, cough, shortness of breath, heartburn, chest pain, dizziness, swelling, fever, chills, night sweats, itching, rash, redness, pain, burning sensation, and bleeding. Some patients experience none of these symptoms. Others may experience several of these symptoms during or after treatment. If you do notice any of these side effects, talk with your doctor. He or she can help determine whether the symptom is caused by the cancer itself or by the radiation therapy.

The good news is that radiation therapy can eliminate the cancer without causing long term harm to healthy cells. And even though it does cause side effects, those side effects tend to go away quickly once treatment ends.

Questions to ask the health care team

Radiation therapy is often used to treat cancer patients. Radiation therapy uses high energy beams of x-rays, protons, or neutrons to kill cancer cells while sparing healthy tissue. Radiation therapy can be used alone or in combination with surgery or chemotherapy. In some cases, radiation therapy is used to shrink tumors before surgical removal.

While there are different types of radiation therapies, each one works differently and has different benefits. Your doctor may recommend one form over another based on what you want to accomplish, how much damage you can tolerate, and where the tumor is located. If you choose radiation therapy, your doctor will discuss your options with you and answer your questions about the procedure. You might hear terms like brachytherapy, stereotactic radiosurgery, proton beam therapy, intensity modulated radiation therapy, and external beam radiotherapy.

Here are five questions to consider when deciding whether to undergo radiation therapy:

1. What type of radiation therapy do I need?

There are several types of radiation therapy, including brachytherapy, proton beam therapy (also called particle beam therapy), stereotactic radiosurgeries (sometimes abbreviated SRS), intensity modulated radiation therapy (IMRT), and external beam radiotherapy (EBRT). Each type of radiation therapy has unique advantages and disadvantages.

2. How many times a day should I receive radiation therapy?

The number of daily treatments depends on the type of radiation therapy you have chosen. For example, if you have had EBRT, you would likely receive radiation therapy 5 days a week for 6 weeks. This means you would receive radiation therapy every weekday for 6 consecutive weeks. After this time, you would stop receiving radiation therapy until the next round of treatment begins.

3. Will my insurance cover all or part of the cost of radiation therapy?

Insurance companies usually pay for most of the costs associated with radiation therapy. However, they may not cover certain expenses such as travel costs, parking fees, and meals outside your home. Talk to your insurance company to find out more information.

4. Is radiation therapy covered under Medicare?

Medicare covers most of the costs associated radiation therapy. However, Medicare only covers the first 30 days of radiation therapy. After that, you must pay for the remaining portion yourself.

5. Can I get radiation therapy at a hospital instead of an outpatient clinic?

Many hospitals offer radiation therapy services. These facilities typically provide better patient care than outpatient clinics because they have larger rooms, more equipment, and more staff members. They also allow you to stay overnight during your treatment.