Radiation therapy is one of the most common treatments for cancer. It is primarily used to treat certain types of cancer—for example, non-melanoma skin cancers, head and neck cancers, early-stage Hodgkin’s disease, and non-Hodgkin’s lymphomas.
More than half of all people with cancer receive some type of radiation therapy to kill cancer cells. Radiation therapy may be your only cancer treatment, or it may be used in conjunction with other cancer treatments, such as surgery and chemotherapy.
Radiation therapy—also called radiotherapy or X-ray therapy—involves treating cancer with beams of high-energy particles, or waves, such as gamma rays or X-rays. Radiation treatments damage cells by destroying the genetic material that controls how cells grow and divide. And while both healthy and cancerous cells are damaged by radiation, the goal of treatment is to hurt as few normal, healthy cells as possible.
You may be worried about radiation destroying healthy cells as well as the cancerous cells. But radiation is much more harmful to cancer cells than it is to normal cells. This is because cancer cells divide more rapidly than do healthy cells. Cells are more vulnerable to damage when they’re dividing, making cancer cells more susceptible to radiation than normal cells are. In addition, normal cells can recover from the effects of radiation more easily than cancer cells.
Your doctor may suggest radiation therapy as an option at different times during your cancer treatment and for different reasons including:
- Before surgery. This is to shrink a cancerous tumor—called neoadjuvant therapy.
- During surgery. So large doses of radiation can be directed at a tumor.
- After surgery. The purpose is to stop the growth of any remaining cancer cells—called adjuvant therapy.
- Combined with other treatments. The purpose is to destroy cancer cells more effectively.
In addition, radiation therapy is sometimes used to shrink tumors to decrease the pressure, pain, or other symptoms that they may cause. This type of treatment is sometimes referred to as palliative care.
Radiation therapy can be delivered in two ways, externally or internally.
External beam radiation is the most common method used. This radiation comes from a machine, such as a linear accelerator. It allows your doctor to treat large areas of your body and in multiple locations if your cancer has spread.
You typically receive external beam radiation on an outpatient basis on a schedule of five days a week for a period of one to eight weeks. In some cases, a single treatment may be used to help relieve pain or other symptoms associated with more advanced cancers.
During a treatment session, you’ll be asked to lie down. You might be positioned with supports to keep you in place and with shields to block radiation from reaching certain parts of your body. The machine may rotate around your body to reach the target from different directions. Treatment sessions generally last 15 to 30 minutes.
Also known as brachytherapy, internal radiation is typically used when your doctor needs to deliver a high dose of radiation to a small area. Rather than coming from machines outside your body, the radiation source is placed inside your body. Most often, the radioactive material is placed inside your tumor or very close to it.
Internal radiation can also be given intravenously through an IV, by mouth, or it can be injected into a body cavity. Your doctor may restrict how frequently and closely you have contact with people while you’re receiving internal radiation treatment. This is because some treatments allow radiation to escape, and it’s important to limit unnecessary radiation exposure to others.
Side effects of radiation therapy greatly depend on which part of your body is being radiated and how much radiation is used. You may experience no side effects at all, or you may experience several. Most side effects are temporary, can be controlled and generally disappear over time once treatment has ended. Some common side effects of radiation therapy included:
- Any body part: Hair loss at treatment site; Skin irritation at treatment site; Fatigue
- Head and neck: Dry mouth, thickened saliva, difficulty swallowing; Changes in the way food tastes; Earaches; Sore jaw; Nausea
- Chest: Difficulty swallowing; Persistent cough; Shortness of breath
- Abdomen: Upset stomach (e.g. vomiting, nausea, diarrhea)
- Pelvis: Upset stomach (e.g. vomiting, nausea, diarrhea); Bladder irritation; Frequent urination; Sexual dysfunction
Questions to ask your doctor about radiation therapy
Some questions you might want to ask your doctor or nurse about what to expect from radiation therapy treatment include:
- What is the purpose of radiation treatment for my type of cancer?
- Will it prevent or stop the spread of cancer?
- Will it destroy or shrink the tumor?
- What are the chances that radiation therapy will work?
- Are there other ways to achieve the same goal?
- If the radiation does not work, are there other treatments for me?
- What are the potential risks and side effects of radiation?
- Will radiation therapy restrict my diet, activities, work, exercise, sexual activity in any way?