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I have to have radiotherapy treatments. What should I expect?

Dr. Khalil Sultanem, radio-oncologist at the Oncology Department at the Jewish General Hospital in Montréal, explains.

What Is Radiotherapy?

Radiotherapy is a type of energy (radiation) from X-rays, gamma rays, electrons and other sources that is used to destroy cancerous cells. Radiotherapy, also known as radiation therapy or irradiation, is a commonly used in cancer treatment. High doses of radiation destroy the cells being treated, thus damaging the genes in their DNA, making it impossible for them to grow and divide.

Radiotherapy is a treatment often recommended for women affected by breast cancer. It is used to maximize local control of the disease in the affected breast(s) and/or nodes. It is frequently recommended as a complement to chemotherapy, but may be recommended on its own in certain cases.

Treatments generally begin about four to six weeks after surgery or chemotherapy. In most hospitals treatment doesn’t begin until after three consultations at least:

Consultation 1: Information Session with a Radiation Oncologist

This consultation with a specialist allows the patient to thoroughly understand the benefits and risks of radiotherapy in order to make an informed decision as to whether to have the treatment or not.

Consultation 2: Treatment Planning via Scanning

This step is very important as it makes it possible to establish a personalized treatment plan adapted to the specific medical condition. A treatment plan is made possible thanks to a scanner that pinpoints the exact location of the tumour. The patient lies down and keeps perfectly still while the scanner takes images and measurements of the treatment area and determines the size of the radiation fields and where they should be directed. This process ensures that the doses of radiation are directed to the exact location while avoiding healthy tissue and organs as much as possible.

Consultation 3: Treatment Planning via Marking

Based on the scanned images, temporary marks are made with a special ink on the skin of the treatment area. These marks delineate the treatment area and are essential reference points to ensure the radiation is directed to the exact same spot every time. These marks are temporary, except for one very small tattoo on the skin, but must remain visible throughout the duration of radiotherapy treatment.


Once the patient and the medical team are ready to begin treatment, the patient meets with a radiotherapy technician in the treatment room. The technician places the patient in the right position under the treatment machine, guided by the marks on the patient’s skin.

The treatment itself is not painful and lasts about five minutes. It lasts about fifteen minutes if preparation time is included. In general, one full treatment is administered over a three to five-and-a-half-week period, at a rate of five sessions per week. The number of treatments depends on factors such as the area being treated, the size of the breast, the size of the tumour and the stage of the cancer.

Possible Side Effects

The risk of a cancer relapse in the same spot is evaluated at less than 10% following radiotherapy. However, side effects are possible. The majority of women tolerate them well and some even cope with them well enough to continue their normal routine between treatments.

Here are some possible side effects, which may last from a few weeks to several months:

  • fatigue;
  • reddened skin on the breast, similar to a sunburn;
  • sensitive or slightly swollen breast;
  • a dry cough in some patients (due to the proximity of the lungs to the breasts);
  • 7 to 10% of women may develop lymphedema in the long run after their treatments.

There are ways to prevent this kind of side effects: maintaining a healthy diet, wearing a soft bra, avoiding nylon garments, and applying an unscented moisturizer three or four times a day (but not in the four hours following treatment).

Contraindications to Radiotherapy

Radiotherapy is contraindicated in the following cases:

  • during pregnancy;
  • in patients who have already received radiotherapy in the same area.