What to expect from radiation therapy

Radiation is generally understood to cause cancer. So, why and how is it used to treat the disease? A Mediclinic expert explains.

In certain doses, radiation can kill some cancers with minimal effect on the surrounding healthy cells, says Dr Charleen Muller, an oncologist at Mediclinic Louis Leipoldt.

“This is because the radiation (or radiotherapy) damages the cancer cell’s DNA, causing it to die before the cell multiplies and spreads,” she explains.

Although this process may take several months, and treatment must be administered several times, radiation has proved highly effective in treating tumours of the breast, cervix, head, thyroid, neck, prostate, and eye.

“Advances in the types of radiation given allows the treatment to be delivered over a shorter time period with equal effectiveness but fewer-side effects,” Dr Muller says.

Types of radiation

Besides its ability to treat cancer, radiation also has the potential to affect healthy cells. Your doctor will consider the unique aspects of your case to decide whether this risk is significant, or whether it is safe to go forward with radiation. Depending on the type of cancer being treated, your doctor may recommend one of three types of radiation:

• External beam radiation therapy. The radiation is administered by a machine that targets the affected body part directly.
• Brachytherapy. The source of radiation, e.g., a capsule containing radiation, is placed inside your body. Brachytherapy is a form of internal radiation therapy.
• Systemic radiation. This is another form of internal therapy in which the radiation source is administered as a liquid or a tablet, so that it’s circulated around your body to the affected part.

The type of radiation will depend on your general health; the size and location of your tumour, especially in relation to healthy cells that may also be sensitive to radiation; and other treatment you’re receiving. This means the plan for your radiation treatment is highly individualised.

What are the side-effects likely to be?

While there are many benefits to radiation, it tends to cause side-effects in the region where the radiation is given. In treating the stomach area, for example, you may develop stomach cramps. Other side-effects include diarrhoea, fatigue, loss of appetite, sore skin, and a loss of hair in the area receiving treatment. Patients may also experience pain in the mouth and may feel generally unwell. These symptoms usually pass four to six weeks after treatment is complete.

Because radiation may harm unborn babies, the treatment is not recommended for pregnant women. Radiation may also affect fertility in both men and women if the treatment targets areas like the ovaries or testicles.

How is radiation used?

Because radiation frequently reduces the size of a tumour, it’s often used in conjunction with other treatments, e.g., a patient may receive radiation to shrink a tumour so it can be removed through surgery. It can also be used during surgery, where being able to home in on the tumour with an external beam helps protect healthy tissues. Radiation is often seen as the preferred approach to treating small tumours or early-stage cancer, because it is localised, so it has fewer side-effects than chemotherapy.

The treatment may also be used after surgery to kill any cancer cells that have remained. This ensures the cancer does not grow back or spread to other body parts. In addition, your doctor may recommend radiation alongside chemotherapy to provide more effective treatment.

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