Oral Cancer: Radiation Therapy
What is radiation therapy?
Radiation therapy is a treatment for cancer that uses high-energy X-rays or rays of other particles to kill cancer cells. In most cases, a large machine directs the rays of energy to the area of cancer. This is called external radiation. But sometimes, radioactive materials are put right into the tumor. This is called internal radiation or brachytherapy. It's not commonly used for oral cancer. But it may be given along with external radiation in rare cases. Radiation therapy is also called radiotherapy. Its goal is to kill or shrink cancer cells.
When radiation therapy is used
Your doctor may advise radiation therapy for you in any of these cases:
Your oral cancer has not spread and the tumor is small. In this case, you may have external radiation as the main treatment.
You have a medium to large tumor. Radiation therapy may be used along with chemotherapy as the first treatment. The goal is to shrink the tumor so it's easier to remove with surgery. This may be called neoadjuvant treatment.
You’ve just had surgery for a medium to large tumor. In this case the doctor may advise radiation, maybe along with chemotherapy. This is done to help make sure the tumor is destroyed and to kill any cancer cells that may have been left behind.
You’ve already had surgery or another treatment and your cancer has come back.
You’re having pain from oral cancer that has spread to your bones, or the tumor is making it hard for you to swallow. In this case, your doctor may advise radiation help shrink the tumor and ease the problems it's causing.
How radiation therapy is done
There are 2 main types of radiation therapy:
External radiation.The radiation comes from a machine and is pointed at the skin over the tumor. External beam radiation therapy is the most common type of radiation given for oral cancer. The treatment is a lot like getting an X-ray. The radiation comes from a large machine. The machine doesn't touch you during the treatment. The treatments don't hurt and they are quick. Radiation from a source outside the body is usually directed at the tumor site.
Internal radiation (brachytherapy). Radioactive material is placed in or near the area of cancer. The radiation material may be put in flexible tubes called catheters or metal rods that were put in during surgery. The radiation only travels a very short distance to kill the nearby cancer cells.
Deciding on a radiation treatment plan
You will talk with a radiation oncologist. This is a doctor who specializes in both cancer and radiation. You’ll work with your doctor to decide what your treatment will be and how long it will last. During your visit, ask what you can expect to feel during and after the treatment.
Before radiation treatment
Before you start radiation, you'll need a dental exam. This is usually done by a dentist who treats patients with oral cancer (oncologic dentist). If your teeth are in poor condition, the dentist will remove them. If all of your teeth need to be removed, your dentist can create dentures for you to wear after the treatment is over and the swelling has gone down. Removing teeth in bad condition helps prevent radiation damage to your jawbone (osteoradionecrosis).
Before external radiation therapy
Before your first radiation treatment, you will have an appointment to learn exactly where on your body the radiation beam needs to be directed. This is a process called simulation. This appointment may take up to 2 hours. Here's what you can expect to happen during the simulation process:
You'll lie still on a table while a radiation therapist uses a machine to identify your treatment field, which may also be called your treatment port. The field is the exact area on your body where the radiation will be aimed. You may have more than 1 treatment field if you have cancer in more than 1 place. The therapist will mark your skin with tiny dots of colored semipermanent ink or with tiny tattoos. In this way, the therapist can aim the radiation at the same place each time and limit damage to nearby healthy tissues.
You may also have imaging scans, such as CT scans, to help doctors know the exact location of your tumor to better determine the treatment area.
You may also have a face mask or other body molds made. Molds are used to hold you in the best position each time. They also help keep you from moving during the treatments.
The radiation oncologist and the radiation therapist will carefully watch the intensity and length of each radiation treatment. They will also check the area that is being treated. You will get regular physical exams and blood tests during the course of your treatments.
What to expect during external radiation therapy
You can get external radiation as an outpatient at a hospital or clinic. That means you don't need to stay overnight. You'll receive a schedule for radiation therapy. The schedule usually is 5 days a week, for 6 to 7 weeks. Spreading out the radiation dose helps protect your healthy tissue. Some people can be treated with newer methods that are given twice daily on some or all of the treatment days.
On the days you have radiation treatment, you'll lie on a table while the machine is placed over you. A face mask may be used to hold you in the right position while the radiation is being given. You may have to wear a hospital gown. A radiation therapist may place blocks or special shields to protect parts of your body that don't need to be exposed to radiation. The therapist may use lights on the machine to line it up with the marks made on your skin during the earlier simulation. The experience is much like that of getting an X-ray, only it lasts longer. It takes about 15 to 30 minutes for the whole process, with about 1 to 5 minutes of that spent getting the radiation.
The radiation therapist will leave the room to turn on the machine, but you will be able to talk to the therapist over an intercom. The therapist can see, hear, and talk to you the entire time. You can't feel radiation so it will be painless. You may hear whirring or clicking noises. The machine may move around you but it will not touch you. You will not be radioactive afterward.
What to expect during internal radiation (brachytherapy)
If you have brachytherapy, you may need to stay in the hospital for a few days while the treatment is done. You may need to limit the amount of time that people visit you because of the radiation inside your body during this time. When doctors remove the implant, your body will no longer be radioactive.
Side effects of radiation therapy
Radiation affects normal cells as well as cancer cells. You may have side effects, depending on how much radiation you get and where you get it. Common side effects after radiation can include:
Dry mouth caused by damage to the salivary glands
Red and sore mouth that may cause pain
Trouble opening the mouth and trouble swallowing
Damaged taste buds and loss of sense of taste
Skin irritation in the area that was treated
Teeth erosion or cavities from having a dry mouth
Many of these side effects will go away a few weeks after treatments end. But some may be long-lasting (permanent). Talk with your doctor about what to expect and what can be done to help manage side effects. You may have fluoride treatments prescribed by your doctor or dentist. These are to help prevent teeth erosion and cavities.
Another rare possible side effect is damage to the jaw bone (osteoradionecrosis). Your risk for this damage is higher if you have bad teeth left in place when getting radiation. That’s why it’s very important to see a dentist before starting radiation.
When to call your healthcare provider
Ask your doctor and nurses what you should watch for and when you need to call them. For instance, you may be told to call if you have signs of infection, such as fever, or side effects that are causing a lot of pain. Be sure you know how to get in touch with your cancer treatment team outside of office hours and on weekends and holidays.
May 12, 2018
NCCN Clinical Practice Guidelines Head and Neck Cancers Version 2.2013, National Comprehensive Cancer Network
Gersten, Todd, MD,Stump-Sutliff, Kim, RN, MSN, AOCNS