If you have cancer, there’s a good chance your doctor has discussed radiation with you. More than half of all cancer patients receive radiation therapy at some point in their treatment. Radiation is known for its effectiveness.
“Radiation uses X-rays to damage the DNA of cancer cells,” says UNC Health radiation oncologist Ashley Weiner, MD, PhD. “Radiation doesn’t directly kill the cancer cells, but once they’re damaged, they won’t grow or divide, cannot repair the damage and eventually will die.”
Radiation is considered a local treatment, because the X-rays are aimed at a specific part of the body, which means the therapy is less harmful to healthy cells that are out of the radiation field. In comparison, chemotherapy is a systemic treatment and can have effects on the entire body.
Dr. Weiner explains what radiation is and what you can expect if you’re preparing to receive treatment.
Types of Radiation Therapy
Radiation may be your only treatment for cancer, or it may be used in combination with other treatments, such as surgery, immunotherapy or chemotherapy, to help provide the best results.
If your care team determines you need surgery to remove cancer, your doctor may recommend neoadjuvant radiation, which takes place before surgery, to shrink a tumor or stop its growth. Adjuvant radiation, which happens after surgery, may be used to target any remaining cancer cells.
Radiation also can be used as a palliative therapy in people with symptomatic metastatic or advanced cancer. If, for example, a tumor is causing pain that affects your quality of life, a short, low-dose course of radiation may shrink the tumor enough to relieve your symptoms.
Most people receive external beam radiation therapy, which involves lying on a table while custom X-ray fields (photon beams) are aimed at the tumor with a machine called a linear accelerator.
It is also possible to deliver internal radiation, or brachytherapy, for some cancers. If you have a gynecological cancer, for example, you might have a tubes or catheters placed in or around the tumor in the cervix or uterus, and a radiation source can release radiation through these instruments during a treatment session. For prostate cancer, radiation “seeds” might be placed permanently and deliver radiation over a few weeks or months.
The Radiation Process
If your doctor recommends radiation, you’ll have a consultation with a radiation oncologist, who will decide whether the treatment is appropriate.
“At that point, we can begin to determine the recommended course,” Dr. Weiner says. “We’ll review with you the dose, the number of treatments and any side effects to expect.”
After the consultation, you’ll have a CT simulation to help plan your treatment. The purpose of the simulation is not to diagnose or find disease in the body; rather, your radiation team is mapping the location and size of the tumor and the precise position you will be placed in for each of your therapy sessions so the radiation can reach its target. You will also have small marks drawn on your body to help guide positioning for the treatments.
As a next step, members of your radiation care team will work together to implement the treatment plan, ensuring the dose of radiation will destroy cancer cells while protecting nearby healthy cells.
“There’s a behind-the-scenes process that can take a couple of days or weeks, depending on the urgency and complexity of treatment,” Dr. Weiner says. “There are several steps of quality assurance and peer review to ensure the radiation dose and plan are right for the patient.”
Thanks to this work, radiation is safe for patients and the people around them.
“There is never a concern that the patient receiving external beam radiation becomes radioactive or exposes others,” Dr. Weiner says.
Once you begin receiving radiation, treatments can be as short as a single session but typically go five days a week for anywhere from one to eight weeks. The appointment itself is brief—you lie on a table for about 15 to 30 minutes while X-ray beams are aimed at the appointed spot—but going every Monday through Friday for weeks can be difficult for some people.
“There can be a lot of day-to-day logistics, especially if you have to drive a long distance,” Dr. Weiner says. Acknowledging that going every day can be a challenge, doctors recommend that you prioritize it—and rearrange your schedule as needed—to have the greatest chance of success with the treatment plan.
Every day, your radiation oncologist will receive imaging taken during the treatment to ensure the plan is progressing as intended. Once a week, your doctor will meet with you to help manage any side effects.
Side Effects of Radiation
As with all cancer treatments, radiation can have side effects.
“In the first few weeks, there are not a lot of side effects other than fatigue,” Dr. Weiner says. “After about two weeks, you may experience some side effects near the treatment site. If you’re having radiation of the head and neck or lung, for example, you may have skin and throat irritation. If you’re having pelvic radiation, you may experience some burning with urination or diarrhea.”
Changes to the skin at the treatment site are both a short-term and long-term side effect of radiation. During treatment, you might find that your skin is dry, itchy or sore. After treatment is finished, your skin pigmentation may change, and you may develop scar tissue. The severity of the skin reaction depends on the area being treated. With breast cancer, for example, the radiation target is typically close to the surface of the skin, while with prostate cancer, the target is deeper within the body.
“If the target for the radiation is deep within the body, the skin will be affected much less than if it’s near the surface of skin,” Dr. Weiner says. “Some people worry about being burned by radiation because of different technology used many decades ago. Now, with modern applications, the skin has less severe reactions, unless the skin is part of the target for the radiation field.”
With palliative radiation, Dr. Weiner says, your radiation team will work to find a small dose given over just a few treatments that will minimize side effects while relieving your symptoms.
If you have questions about radiation as an appropriate cancer treatment for you, talk to your doctor. Need a doctor? Find one near you.