Radiation therapy at a glance
- In radiation therapy, oncologists use high doses of radiation to shrink tumors and kill cancer cells.
- Radiation therapy techniques include external beam (delivered by a machine outside the body), internal (radioactive material implanted on or near the cancer), and systemic (delivered in the blood to all the body).
- Oncologists use radiation therapy to treat many kinds of cancers, and about half of all cancer patients receive some form of radiation therapy.
- Radiation therapy can be curative, in which oncologists cure or reduce the cancer, or palliative, with the objective of reducing symptoms of the cancer to make the patient more comfortable.
- Radiation therapy may lead to side effects that differ depending on the area of the body treated, and these generally disappear after treatment.
What is radiation therapy?
Radiation therapy uses high doses of radiation to kill cancer cells and shrink tumors. Special equipment directs the radiation onto the cancer cells or tumors. This prevents the cancer from growing, which it does by creating more cancer cells. Radiation therapy targets the cancer cells, whereas chemotherapy uses drugs to treat the entire body.
Radiation therapy kills the cancer cells by damaging their DNA, causing the cells to stop dividing and die. Radiation also works by creating free radicals (charged particles) that damage the cancer cells’ DNA. The dead cells are broken down and removed by the body’s natural processes.
Radiation sometimes affects healthy cells as well as the cancer cells it targets. Cancer cells treated with radiation can’t repair themselves. However, healthy cells affected by radiation can repair themselves.
Radiation therapy treats many kinds of cancer, including breast, prostate, lung, bone, brain and others. According to the National Cancer Institute, close to half of all cancer patients receive radiation therapy during their course of treatment.
Radiation therapy may be used to cure a cancer. But it also may be used with the goal of making the patient feel better by slowing the growth of the cancer.
Radiation therapy is used sometimes along with other treatments and sometimes it is the only treatment. The three types of radiation therapy techniques are external-beam, internal and systemic.
External-beam radiation therapy uses a machine located outside the body to deliver radiation to the area of the body being treated for cancer. The radiation targets the tumor and cancer cells to minimize damage to healthy tissue.
External radiation is painless and is a similar experience to receiving an X-ray. Depending on where the cancer is located, an immobilizer may be needed to ensure the treatment is delivered to the exact same spot each time.
Treatments last about 15 minutes and occur four to five days a week for three to nine weeks. The two to three days off between weekly sessions allows the healthy tissue around the affected area to heal.
Oncologists use different types of external-beam radiation therapy, depending on several factors. Probably the most common type used is 3-dimensional conformal radiation therapy.
Many patients going through external beam radiation therapy are able to go to work and continue their normal routines during therapy.
Internal radiation therapy, or brachytherapy, places implants filled with radioactive material inside the body, in or near the cancer. The radioactive material is sealed in seeds, wires, needles or catheters that doctors insert into the body near a tumor or directly inside it.
Internal radiation therapy allows for a higher dose of radiation to a smaller area than external-beam radiation, which minimizes damage to healthy tissue. Some types of implants are permanent and others are only placed for a few minutes or days at a time.
If the implants are permanent, they will cease to be radioactive over a period of time. It could take weeks or months depending on the type of implant and dosage of radiation used.
Systemic radiation therapy involves sending radiation through the entire body to attack cancer cells. Care providers either give the radiation orally to patients or inject it into the body. The blood then carries the radioactive substance through the body to locate and kill cancer cells.
Systemic radiation therapy is often used for patients with prostate, bone and thyroid cancers. Patients undergoing systemic radiation may need to spend days or weeks in the hospital in order to contain the radiation during treatment.
Side effects of radiation therapy
Radiation therapy may cause side effects that depend on the part of the body being treated, the amount of radiation used and other factors. The radiation oncology care team will discuss all aspects of possible side effects with each patient.
Many patients who receive radiation therapy experience no side effects. Some patients may experience one or more side effect(s).
Side effects are primarily due to damage done to healthy tissue. Oncologists can control these side effects with medications, diet changes and lifestyle management. Over time and after treatment, these side effects disappear. Sometimes long-term side effects may remain.
Side effects that may only affect the patient during or just after treatment include:
- Skin problems such as dryness, redness, blisters and sores
- Hair loss immediately around the area being treated
- Eating problems.
What patients can do during radiation therapy
Radiation therapy patients should take special care of themselves while undergoing treatment. Getting plenty of rest is very important. Radiation therapy can cause people to be more tired than normal, which can last for up to six weeks following the end of treatment.
Eating the right foods can help patients deal with the radiation therapy. Oncologists, nurses and nutritionists can work with patients to make sure they are eating the specific foods their bodies need during radiation therapy.
Some patients may need to add more calories to their diet, and our dietitians can help devise an eating plan to do that. It’s a good idea for patients to keep healthy snacks handy.
One of the most important things a radiation therapy patient should do is ask questions – any questions. Doctors and nurses want to answer all questions a patient or family member may have. Cancer treatment is specific for each person and open communication among patient, physicians and nurses is essential to developing the right radiation treatment plan.
Patients and family members may want to ask such questions as:
- How will we know if the radiation is working?
- What is the goal, to cure the cancer or relieve symptoms?
- What side effects may occur?
- Will radiation therapy alter the patient’s emotions, possibly leading to depression?
- Does radiation therapy affect one’s appetite?
- How do patients deal with the fatigue that may be a side effect of radiation?
Oncologists and oncology nurses can help patients with any aspect related to radiation treatment and the ways it may affect them. For example, oncologists can give patients advice on how best to deal with any side effect, including suggesting simple lifestyle practices that can minimize side effects and increase the person’s day-to-day comfort.