What is Radiotherapy?
Radiotherapy is a cancer treatment that uses radiation to destroy cancer cells and stop them from spreading. This treatment takes days or weeks to start working but continues to work for weeks or months after the radiotherapy is completed.
Radiotherapy has a number of uses particular to head and neck cancer, including:
- Treating particular Stage I and II head and neck cancers
- Treating cancer of the larynx (voicebox), oropharynx and hypopharynx where the aim is to preserve the anatomical function as much as possible
- Treating head and neck cancers that have spread to multiple lymph nodes
- Treating head and neck cancers that have spread to nearby nerve fibres in the head and neck region
- Making sure that residual cancer cells are destroyed after surgery
- Shrinking incurable tumors to prevent them from pressing up against normal tissues and causing pain or other complications
Types of Radiotherapy
There are different types of radiotherapy, named for the way in which radiation is delivered to the patient. When the radiation source comes from outside the body, the treatment is known as external beam radiation. Advances in external beam radiation have given rise to newer techniques, such as intensity modulated radiation therapy (IMRT) and stereotactic radiotherapy that are able to deliver more precise doses of radiation with greater accuracy at cancer targets while sparing the surrounding tissues.
In internal radiotherapy, the radiation source is implanted inside the body near cancer cells. There are two variations of internal radiotherapy: brachytherapy and radioisotope therapy. In brachytherapy, a solid radiation source is implanted next to cancer cells, delivering a high dose of radiation with very little spread to nearby normal tissues. In radioisotope therapy, a liquid source of radiation is either ingested or injected into the body.
Your multidisciplinary treatment team will consult with you to explain which type of radiotherapy will work best to treat your head and neck cancer. The type of radiation, the dose and the schedule (how often is it given) will depend on your general health, the cancer stage, and whether the cancer has spread to nearby lymph nodes, nerves or other areas in the body.
Standard radiotherapy schedules involve giving a single dose (or fraction) of radiation to patients five days a week for seven weeks. Understanding more about how radiotherapy works to control cancer has led to the use of newer scheduling practices called “altered fraction radiotherapy”, where the radiation schedule is either accelerated or hyperfractionated. For the accelerated schedule, the overall radiation treatment time is reduced, which leaves less time for the cancer to regrow between sessions. For the hyperfractionated schedule, two to three lower doses of radiation are given daily, which may lead to fewer side effects.
Side Effects of Radiotherapy
Despite the technological advances in using radiotherapy to target cancer cells, normal cells that are either rapidly dividing or situated close to the cancer cells being treated can also be damaged by the high energy x-ray beams of the radiation. This bystander damage to normal cells during radiotherapy can lead to a number of unwanted side effects such as:
- Mouth sores
- Swelling or drooping of skin
- Stiff jaw
- Dry mouth
- Difficulty swallowing
- Changes in taste
- Hair loss
Special measures will be taken to minimize the side effects from radiotherapy. Your physician will select the dose of radiation that will kill cancer cells but cause as little damage as possible to the nearby tissues. Radiation treatment may also be spread out over the course of one day or many weeks and that will give normal cells a chance to recover from the treatment.
Depending on the nature of your cancer, IMRT or stereotactic radiotherapy might also be used to deliver more precise doses of radiation with greater accuracy to the tumor. During radiotherapy treatment, you may need to take medications that protect parts of the body, such as the salivary glands, that are particularly sensitive to bystander damage from radiation.
How to Prepare for Your Therapy
It is very important for your mouth to be in the best possible condition before you receive radiotherapy for head and neck cancer. Seeing a dentist at least two weeks before radiotherapy will help to prepare your mouth and ensure that it has time to heal after dental work is completed.
If you are having IMRT, you may need to undergo a treatment simulation session where a number of scanning procedures are used to pinpoint the exact location where the radiation will be delivered. You may also need a special device that will help you to keep still during the procedure, and your skin may need to be marked with ink to provide a target guide for the radiation equipment.
If you are having stereotactic radiotherapy, you will be asked to wash your hair with a special shampoo before the procedure. You will not be able to eat or drink anything after midnight before the treatment. You will also be asked to remove all jewelry, makeup, contact lenses, eyeglasses, dentures and hairpieces. Be sure to let the radiation oncologist know if you are taking any special medications, if you have any particular medical conditions or allergies, or if you suffer from claustrophobia.
Regardless of the type of radiotherapy you receive, plenty of rest and mental preparation will help to put you in the best possible frame of mind before your treatment.
During Your Therapy
The schedule for radiotherapy varies depending on the type of treatment being received. The standard radiotherapy schedules involve giving a single dose or two daily doses in selected patients five days a week for six to seven weeks. IMRT is more commonly used at Princess Margaret Cancer Centre and usually involves five 15-30 minute sessions per week for six to seven weeks. Regardless of the radiation treatment you receive, it is a good idea to have a support person who can accompany you during your treatments and take you home when the treatments are finished.
Maintaining your weight during radiotherapy is also very important since your body will need all its strength to heal after the treatment. Your nutritionist will plan a diet for you to follow during the course of your radiotherapy treatment to help keep your weight constant.
You will need to see your radiation oncologist and head and neck specialist about three to six weeks after you finish your radiation treatment. At that visit, they will let you know the outcome of the radiation therapy and discuss the long-term considerations.
Patients who have had radiation to treat head and neck cancer will need to be closely monitored for the rest of their lives. During regular check-ups, your physician will evaluate your general health and assess whether the cancer treatments were effective. It may be necessary to have repeat blood tests and/or diagnostic tests to check for the recurrence of cancer. Your dentist will also monitor the oral cavity during regular dental check-ups.
Remember to monitor how your body feels so that you can let your doctor(s) know during the regular check-ups about any changes that are worrisome, such as:
- constant pains
- unexplained weight loss
- lumps, rashes, bruises, swellings, bleeding
- fever, cough, or persistent hoarseness
Depending on the treatments needed, patients may also have to undergo a period of rehabilitation to help restore bodily functions. Various members of the multidisciplinary treatment team, such as physiotherapists and speech therapists, will be involved in your ongoing rehabilitation to help you regain swallowing movement and/or speech. These professionals will also make referrals for community support upon your return home.