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Radiation Therapy

Radiation therapy (also called radiotherapy) uses radiation (high-energy rays) to kill or shrink tumour cells.

Radiation therapy is administered only at our regional cancer centres. 

Patient booklet

If you are at the start of your radiation therapy, you probably have some questions. Our patient booklet Radiation Therapy: What to Expect provides you with some important information about radiation therapy and help you understand what to expect during your treatment.

About this treatment

Radiation therapy is used to treat some, but not all cancers. About 55% of patients with cancer receive radiation therapy as part of their treatment. 

Radiation therapy destroys cells either directly or by interfering with cell reproduction. Normal cells are able to recover from radiation damage better than cancer cells.

Used alone, radiation therapy can cure cancer in many cases. It is also used in combination with other treatments or therapies such as surgery or chemotherapy. It might be used to both reduce the size of tumours before surgery or to destroy any remaining cancer cells after surgery.

Radiation therapy is also used with many other conventional cancer treatments such as chemotherapy and hormone therapy.

When cure is not possible, radiation therapy can also help improve symptoms such as pain, or extend the patient's length of life, or improve the quality of life for patients.

Radiation therapy is the principal treatment for various skin cancers (non-melanoma), cancers of the mouth, nasal cavity, pharynx and larynx, brain tumours, and many gynecological cancers, as well as lung and prostate cancer.

Radiation therapy is also used in combination with other treatments and therapies for breast, bowel, testicular, childhood, and bladder cancers, as well as Hodgkin's disease, leukemia and lymphomas as well as many other cancers.

Brachytherapy is widely used to treat various types of cancer. The term brachytherapy refers to the placement of radioactive "seeds" or "sources" inside or next to a tumour. The seeds/sources deliver radiation directly to the tumour, sparing surrounding healthy tissue. Some patients experience fewer side effects because healthy tissue is not dramatically affected by brachytherapy. Sometimes brachytherapy is used instead of surgery.

In some cases, thin needles are used to insert the radioactive seeds. Or sometimes, hollow applicators are used to place seeds/sources into body cavities such as the vagina or esophagus. The seeds are tiny and cause little discomfort and are left in the body once all the radiation is used up.

Over the past decade, treatment of prostate cancer has become one of the most common applications for brachytherapy. In a procedure called Transperineal Implantation of the Prostate (TPIP), multiple, tiny, radioactive seeds (over 100 per patient) are inserted into the prostate. This is a 2-hour, outpatient procedure done under general anaesthetic. Using ultra-sound guidance, needles are inserted through the perineum and into the prostate gland to enable placement of the radioactive seeds. Since 1998 over 3500 men in BC have received TPIP and long-term outcomes are very favourable. Prostate brachytherapy achieves excellent control of the cancer and is convenient. For selected patients, it can reduce recovery time and reduce the likelihood of side effects such as impotence and incontinence, compared to the alternative treatments for prostate cancer (such as radical prostatectomy or 7 weeks of daily outpatient visits for standard, external beam radiation therapy).


Intensity Modulated Radiation Therapy (IMRT) is a specialized way of using radiation therapy and computer algorithms called 'inverse-planning' to increase the ability to shape high-dose radiation to the size and shape of a patient’s tumour.

IMRT allows the delivery of higher radiation doses with less damage to surrounding healthy tissue. For example a tumour of the tonsil can receive a curative dose of radiation while the parotid gland that sits superficial to the tonsil can be relatively spared. This enables the parotid gland to continue producing saliva, reducing long-term dry mouth problems that used to be a common with standard radiation therapy for tonsil cancer.

IMRT may also be helpful for patients who experience a recurrence of disease in an area already treated with conventional radiation therapy.



Receiving treatment

Patients in B.C. and the Yukon who require radiation therapy will receive treatment at one of BC Cancer's comprehensive cancer centres where a full range of equipment and expertise is available.

If you or someone you love will be having radiation therapy treatment at BC Cancer, be assured that radiation therapy treatment procedures are explained to patients in full detail before the first scheduled treatment session. This gives patients a chance to have any concerns or questions addressed before the start of treatment.

How it feels

Patients don’t see or feel radiation and are not radioactive following treatment. In most cases, the same amount of radiation will be given each day throughout the course of the treatment plan. After treatment, patients can usually continue with normal activities although they may tire more easily.

If special instructions are required, you will be told about them before treatment begins.

The radiation therapy team

The primary team consists of radiation oncologists, radiation therapists and radiation physicists who work together to decide if radiation therapy will be beneficial. If so, they will design a radiation therapy treatment plan that will be safe and effective for the individual patient's needs.

Two or three radiation therapists then work with the patient to deliver the treatment plan. Radiation therapy may be complete in a single treatment, or delivered daily (Monday through Friday) for several weeks.

Other health-care professionals within the cancer centre, such as nurses, registered dietitians and counsellors will also participate in the patient's care and treatment as required.

Side effects

Coping with side effects

Most patients will experience some kind of side effect after receiving radiation therapy. A support team (radiation therapist, oncologist, nutritionist, and counsellor) will be there to help patients. We have a special section of our website for side effects and coping. Check our Coping with Cancer section for help with nutrition, emotional, financial and practical support, how to deal with symptoms and side effects, and information about palliative care.

What causes side effects?

Because radiation usually passes through some healthy tissue on its way to the tumour, normal cells can be damaged. That is what causes side effects. Attending the cancer centre for a series of radiation treatments can be time-consuming, inconvenient and stressful. Radiation therapy often causes some general fatigue which can be addressed by regular exercise or an afternoon nap. Other, specific side effects of radiation therapy are determined by the area that is treated. 

Possible side effects

Possible side effects of radiation therapy include:

  • Temporary or permanent hair loss in the area being treated. For example, scalp hair will only be affected if the head receives radiation.
  • Skin irritation causing redness or sometimes blistering
  • Some darkening of skin color in the area being treated
  • Swallowing - discomfort or pain - only if radiation is delivered to the throat or central chest
  • Diarrhea - if the abdomen or pelvis are treated
  • Nausea (rare)
  • Low blood count (rare, unless given in combination with chemotherapy)
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