Cancer treatments - radiotherapy

Radiotherapy uses precisely targeted x-rays to destroy cancer cells while limiting the effect of radiation on nearby healthy cells. It can be used to treat cancer in many parts of the body. The length of a course of treatment varies depending on factors such as the location, type and stage of the cancer, and whether the radiotherapy is combined with other treatments such as chemotherapy or surgery.

How radiotherapy decisions are made#

Before deciding whether radiotherapy is appropriate for your condition, your case is usually discussed at a meeting of the healthcare team. This brings together the medical specialists involved in caring for your particular type of cancer, which may include surgeons, medical oncologists, radiation oncologists, pathologists and radiologists.

At these meetings, the team:

• reviews all the information relating to your case
• considers relevant details, which may include your lifestyle
• looks at the results of various tests

They then offer specialist advice on the best way to treat your cancer.

Depending on the purpose of treatment, some people have a single radiotherapy session while others have regular treatments over one to eight weeks. Radiotherapy is usually (but not always) given once a day, five days a week, and takes only a few minutes each time. It can be delivered by a variety of machines and devices, depending on which part of the body is affected and the type and stage of the tumour.

Radiotherapy may be used:

• as the only treatment
• together with chemotherapy
• before surgery, to shrink the tumour
• after surgery, to kill off any remaining cancer cells
• as a way to relieve pain and ease symptoms such as bleeding

The two main types of radiotherapy#

The two main types are external and internal radiotherapy. Most people have only external radiotherapy, but some need both, depending on the site and type of cancer.

External radiotherapy#

External radiotherapy is given in hospital by a team that may include a radiation oncologist (a medical cancer specialist) and a radiation therapist (a specially trained health professional). Other team members may include medical physicists, nurses and other allied health professionals.

Before treatment begins, the precise area to be targeted is identified, often using a special computed tomography (CT) scanner. Magnetic resonance imaging (MRI) and positron emission tomography (PET) scans may also be used. This step is often called ‘simulation’ or ‘planning’. Your radiation oncologist prescribes your individual treatment plan, including the radiation dose and the exact area to be targeted. The radiation therapist then calculates the details based on information from the simulator and your scans.

To keep you still and accurate during treatment:

• If you are being treated around the head or neck, a cast of your upper body may be made and worn during treatment so your head does not move.
• In other cases, snug-fitting supports may be placed around your body to keep you stable.
• Some treatments require you to lie face down in a special cradle or on a belly-board, which keeps part of your bowel outside the treatment area.

The radiation therapist may mark the treatment area on your skin with non-permanent ink to help line up the equipment correctly. Once the ideal position is found, a tiny permanent skin mark may be added so that further treatments are delivered accurately. You may also be given a contrast agent (also called contrast medium or dye) to swallow or have injected into a vein, which helps internal organs and structures show up during treatment.

Having external radiotherapy is similar to having a regular x-ray. Anaesthesia is not needed (except for infants), and usually no medication is required beforehand. If treatment is likely to cause nausea or vomiting, you may be given medication to prevent this before each session.

The machine that delivers the high-energy x-rays is called a ‘megavoltage machine’ or ’linear accelerator’. During treatment:

• You lie on the treatment table beneath the machine.
• The radiation therapists position your body so the treatment precisely targets the area to be treated, using information from your planning procedure and your oncologist’s prescription.
• Blocking devices, called shielding, protect parts of your body that do not need treatment.
• Staff leave the room to operate the machine but can see you on a monitor and talk to you over an intercom.

Treatment takes a few minutes and is painless. You will hear a drone, similar to a vacuum cleaner, while the machine works. The therapists may reposition the machine to treat from different angles, which can often be done remotely. They may also take an electronic x-ray of the treatment area to check accuracy and allow for minor adjustments due to body movement.

Traditional external radiotherapy uses multiple fields of treatment — back to front, side to side or at oblique angles — and you do not need to move, because the machine can rotate right around you. Increasingly, computers are used to shape, or ‘modulate’, the beam to improve accuracy and reduce the chance of treating areas that do not need it. This is known as intensity-modulated radiation therapy, and may be delivered with the beam fixed or rotating around your body.

External radiotherapy does not make you radioactive. As soon as the machine is switched off, there is no radiation in you or the room, and you can be near other people with no concern for their safety.

Internal radiotherapy (brachytherapy)#

Sometimes a specialist recommends both external and internal radiotherapy, depending on the cancer. Internal radiotherapy, also called brachytherapy (from the Greek for ’treatment from a short distance’), is given from a localised implant. The procedure generally involves:

• placing hollow tubes of different shapes, or hollow needles, inside your body through or around the tumour
• a precisely controlled computerised machine placing a radiation source inside these tubes or needles

How long the source stays in depends on its strength and the dose required. Treatment may be a single session or repeated several times. Brachytherapy is commonly used for cancer of the cervix, uterus, vagina and prostate gland, and may also be used for other cancers.

There are two types of radiation source:

• a low-dose-rate source that works slowly over a number of days, such as radiation seed implants
• a high-dose-rate source that works very quickly and takes only minutes

Most treatments now use high-dose-rate sources, which may require between one and five sessions on separate occasions. Implants come in different sizes and shapes, including needles, plastic tubes, catheters, capsules and rods, depending on the cancer and the area treated. Some are placed in existing spaces inside the body (intra-cavitary implants) and others are placed through the skin near the cancer (interstitial implants). The implant is inserted under anaesthetic.

Brachytherapy implants can be temporary or permanent:

• A temporary implant is removed after treatment. It may be re-inserted each time or left in place for a few days to complete treatment before removal.
• While the source is inside the needles or tubing, your body emits small traces of radioactive energy. Once the source is withdrawn, there is no radiation left in your body, even if the implant remains.
• While being treated in the brachytherapy room or suite (which may be in an operating theatre), staff watch you closely from a shielded room and can start and stop treatment as needed. Most treatments take a few minutes and you feel no sensation from the treatment itself.

After a temporary implant is removed, it is unusual to have symptoms, although swelling may occur if needles were used. Bleeding and infection are very rare but may happen and require medical care. With low-dose-rate treatment in hospital, the source may stay inside the tubing for up to 40 hours, and you are kept isolated from staff and others during this time. This type of treatment is now less common.

A permanent implant usually uses radiation seeds (especially for prostate cancer). These stay in place, delivering therapy over days and weeks, but the seeds gradually weaken and eventually stop being radioactive after some months, depending on the type used. In the first few days after insertion, hospital staff keep you in a single room and limit time with visitors, especially children and pregnant women. The radiation fades over time, so others will be safe to be near you once you are discharged. You will be given special instructions about being close to children and pregnant women while the sources are still active inside the body.

Side effects of radiotherapy#

Radiotherapy works by killing cells that divide rapidly, which is why it is effective against cancer. It can also affect healthy cells that naturally divide quickly, such as those lining the gut, the skin, the bladder and the bone marrow — and this is why side effects occur. Not everyone has side effects, but usually one or two appear. They depend on the type and dose of radiotherapy and the part of the body treated.

After treatment finishes, almost all side effects disappear. Some may return after months or years and may affect other tissues in the treatment area. It is important to discuss side effects with your doctor, because treatments are available.

General side effects may include:

• skin changes — including dryness, reddening, itching, blistering, flaking and tanning
• superficial ulceration, which usually heals in two to six weeks
• fatigue
• nausea or loss of appetite
• hair loss (alopecia) in the area being treated

Heat, sunlight, harsh soaps, chemicals, dyes and abrasive washing can make skin symptoms worse. Your radiotherapy nurse will discuss skin care with you, and you may need special gels, creams and dressings.

Other possible effects, depending on the area treated, include hair loss from treated areas such as the head, face, armpits and pubic region; a burning sensation when passing urine or a need to urinate more often; bleeding (rarely); and vaginal dryness and discomfort. If the ovaries are within the treatment field, they may stop working, and menopause may affect some women. People with prior bowel disorders, such as diverticular disease, may find their symptoms worsen.

Tell your doctor at once if you have severe or distressing side effects that do not respond to medication, such as severe vomiting, ongoing diarrhoea, bleeding or any other change in your health that worries you. If you cannot reach your doctor, go to the emergency department of your nearest hospital and tell staff you are having radiotherapy.

Coping with side effects#

Remember that almost all side effects disappear once treatment is complete. In the meantime, helpful strategies include:

• Rest as much as you can. Plan activities for times when you feel most energetic, perhaps in the mornings, and take afternoon naps if needed.
• Exercise gently whenever possible.
• Avoid sun exposure. When outside, wear protective clothing such as a broad-brimmed hat and a long-sleeved top, and ask your doctor before using sunscreen on exposed skin.
• Avoid perfumes, deodorants, soaps, creams and make-up on the treatment area; use a soap-free wash instead.
• Avoid scratchy or stiff clothing, hot showers or baths, scratchy towels and shaving the treatment area.
• Do not scrub the skin over the treatment area.
• Avoid over-the-counter medicines, natural therapies and other supplements unless your doctor says they are okay.
• Seek help if you feel depressed or anxious. See your doctor for advice and referral if talking with family and friends does not help.

If you are having radiotherapy to the head and neck:

• Use gentle shampoos and avoid harsh hair treatments such as dyes, perms, rollers, gels and sprays, which can worsen hair loss.
• Try satin or cotton pillowcases, which may feel more comfortable against your scalp.
• Choose high-energy foods. If you do not feel like eating, try supplemented drinks such as milkshakes with egg, honey or supplement powders.
• Avoid over-the-counter mouthwashes, alcohol and cigarettes, as this treatment can cause swallowing problems and a dry mouth. Your doctor may prescribe artificial saliva products, and a speech therapist can assess swallowing and speech difficulties if needed.
• Avoid food and drink that is too hot or too cold, and visit your dentist before, during and after treatment to manage dental problems such as decay.

If you are having radiotherapy to the chest, abdomen or pelvis:

• Avoid high-fibre foods if treating the abdomen, as treatment can cause nausea and diarrhoea. Choose bland foods such as toast or dry biscuits, avoid spicy food and food with seeds, and snack lightly through the day rather than having three large meals. Specific medication may be needed.
• For radiotherapy to the cervix, uterus, bladder, bowel or other pelvic areas, using a vaginal cylinder and hormone cream may help prevent narrowing and drying of the vaginal lining. Sexual function may be affected and can be discussed with your doctor or nurse, and referral to a gynaecologist may help. Fertility and hormonal function may also be affected and should be discussed with your specialists.
• For a burning sensation when passing urine, or a need to urinate more often (a common effect of radiotherapy to the bladder region), reducing acid in your urine can help. Medication is available, but discuss ongoing or severe symptoms with your doctor.

During treatment, your doctor will order tests such as physical examinations, x-rays, other scans and blood tests to see how you are tolerating treatment. During the course it can be hard to tell how well radiotherapy is working; this is usually assessed after the full course is complete.

Key points#

• The length of treatment varies depending on the location, type and stage of the cancer.
• The two main types of radiotherapy are external and internal.
• If you are having treatment to your head or neck, a cast of your upper body may be made and worn during treatment so your head does not move.
• Almost all side effects disappear once treatment is completed.

Where to get help#