Radiotherapy (RT) is a high-energy, targeted X-ray treatment which kills tumour cells by damaging DNA. It’s an important modality used to treat many cancers and advanced technologies are revolutionising its applications, allowing for improved cancer outcomes while reducing side effects.
You can listen to this article below, or by using your favourite podcast player at pod.link/oncologybuddies
Types of radiotherapy
External beam radiotherapy is the most commonly delivered type, whereby you are positioned on a bed or couch and the radiotherapy machine moves around you to deliver X-rays, which are called photons.
Brachytherapy refers to tiny radioactive seeds being placed in or near a growth. A radioactive seed may be placed inside a body cavity – such as the swallowing tube (for cancer of the oesophagus) or inside the vagina at the mouth of the womb (for cervical cancer). This is usually temporary with the process taking anything from 15 minutes to two hours after which the seed is removed.
Sometimes many seeds are implanted during a surgical procedure (for prostate cancer); this is a permanent procedure, and the seeds will remain inside you. With many trials and studies underway across the world and with new evidence being presented daily, the art of radiotherapy is being refined more and more and this will result in better treatment decisions being made for every patient. Should you be uncertain about any aspect of your treatment, ask your oncologist to explain as it’s important for you to know what to expect.
Preparing for radiotherapy
External beam radiotherapy is usually given once a day on weekdays (Monday to Friday), excluding weekends and public holidays. For certain conditions this may differ, sometimes you may receive treatment twice a day or alternate days. The treatment, including set-up, takes about 15 – 20 minutes in most cases. The overall treatment course may range from one day to several weeks, depending on your case. Special devices may be required, to aid immobilisaion and limit movement, such as customised masks and body casts. These will be fitted prior to starting treatment.
Radiotherapy is delivered by a team of highly qualified health professionals. Specially-trained radiotherapists, who work at the RT units, are responsible for positioning you daily and delivering the treatment that has been planned and prescribed by your clinical or radiation oncologist. They take set-up X-rays and scans to check accuracy and then adjust as necessary. Your doctor also checks these X-rays to ensure that treatment is delivered as planned. These X-rays aren’t to assess treatment response; this can usually only be assessed in the weeks to months following completion of RT.
RT planning CT scan
The first step is to have a RT planning CT scan in the treatment position; this will be reproduced at each treatment. This scan isn’t to be confused with a diagnostic CT scan. This usually takes place one to two weeks before treatment starts and takes up to two hours, from counselling to set-up to the scan. It’s useful to bring any relevant discs of scans done related to your cancer, such as diagnostic CT, MRI and PET scans. These greatly aid the RT planning process.
For certain tumours, specific protocols are used to improve accuracy of treatment delivery and/or to reduce the dose to the normal surrounding organs. This will be explained in greater detail by the radiotherapists at the time of the scan.
Pelvic treatments (rectal, anal, gynaecologic and urologic cancers) are often done with a full bladder and sometimes also with an empty rectum.
Upper abdominal treatments (oesophageal, stomach and pancreatic cancers) are usually done, fasting for two to three hours, if possible.
Upper abdominal and chest treatments are also often done using a specialised breathing technique, Deep Inspiration Breath Hold or Respiratory Gating, to improve accuracy and reduce the dose to surrounding organs at risk.
Following this, the doctor, planning radiotherapists and medical physicists spend time working on your radiotherapy plan and it’s quality assurance checks. Once these have passed, the treatment is ready to begin.
Weekly on-treatment reviews
You are usually seen regularly (usually once a week) by your oncologist. This review is important to assess how you are tolerating treatment and to manage side effects.
Chemotherapy concurrently with radiotherapy
You may have chemotherapy and radiotherapy together. If the chemotherapy is given intravenously, it may be done once a week before radiotherapy or for several days at the start or towards the end of treatment. If the chemotherapy is given orally, it’s usually taken on the days of radiotherapy.
Be prepared for side effects
Radiotherapy side effects may be generalised, but many are specific to the area being treated. Your doctor will discuss more about these during the consultations. Usually, you won’t feel any physical effect when radiotherapy is delivered. However, some side effects may develop with time, and these may be uncomfortable or even painful. Not everyone will experience the same side effects. It depends on many factors, including your sensitivity as well as the area being treated, and the dose of radiotherapy required.
Common side effects
RT side effects are divided into early and late side effects. Early (acute) side effects may occur from the start of radiotherapy or within three months. They tend to be quite common but are usually transient and reversible. Late (chronic) side effects, may occur at any time beyond three months from radiotherapy, even years later. These tend to be less common than early side effects but may be chronic and long-lasting.
The severity varies from patient to patient and may range from mild to severe. A study showed that exercise helps reduce radiotherapy-related fatigue. Don’t overdo it and rest when needed.
Loss of appetite
Be sure to follow a well-balanced diet and maintain a healthy fluid intake.
Nausea and diarrhoea
Usually mild. Medication may be used.
Usually mild. Medication may be used.
Vary depending on the area being treated. The more superficial a treatment needs to be (skin-, breast- or anal cancer), the higher the likelihood of a skin reaction occurring. Early skin effects which occur while on treatment include redness, dryness and itchiness. As you progress through treatment, areas of skin in the treated area may start to peel; this may be a dry peel or progress to a weepy, wet peel or even ulceration. Your doctor will explain how to care for the skin to reduce the severity of the skin reaction.
The early skin reaction usually heals with time but may require special creams or dressings. As a late effect, the skin in the treated area may become hard and stiff. Sometimes there are also pigmentation changes (darkening or lightening) and the development of thin, red blood vessels visible under the skin.
As a late effect, the soft tissues and muscles of the areas being treated may harden and become stiff.
Weight loss and even malnutrition
May be encountered if you’re undergoing radiotherapy of the gastrointestinal tract (from the mouth all the way down to the anal canal). This may be due to the tumour itself or due to some of the above-mentioned side effects. It may be of benefit to see a dietitian who will advise regarding optimal nutrition.
Anxiety or depression
It’s important to recognise this early and to seek help. Counselling is highly recommended for you and your caregivers. Don’t be afraid to reach out for help and support.
Other side effects
Depending on the area being treated and the radiotherapy dose, you may experience burning urine, hair loss, shortness of breath, cough, heartburn, pain due to inflammation, bone changes, infertility, second cancer risk and others. These should be discussed in greater detail by your treating team.
- It’s important to avoid chemicals, sun exposure and anything else which may aggravate the skin reaction.
- Gentle skincare of the treated area may help limit side effects.
- Keep the area being treated clean and dry.
- Wash with lukewarm water and fragrance-free soap.
- Use of fragrance-free, water-based moisturisers, such as aqueous cream.
- Avoid the use of perfumes and baby powder.
- Avoiding friction by wearing loose-fitting, soft clothing.
If you experience any severe symptoms, proceed to your nearest casualty and inform your doctor as soon as possible.
Head and neck treatment
For head and neck cancers requiring radiotherapy (often in combination with chemotherapy), the mucous membranes of the oral cavity and pharynx may become inflamed. This may cause pain and burning. Your doctor will usually prescribe mouth washes and pain medication to help manage this.
You may be prone to oral thrush (bacterial, viral or fungal infections). This may also be painful and require medication.
Loss of taste
You may experience this which is often also accompanied by a change in sense of smell. The change in taste sensation usually starts within the first two weeks of treatment. Taste sensation usually improves again, but this may take months and never quite return to normal.
This early side effect starts while on treatment but persists as a chronic complication. This happens because the salivary glands are particularly sensitive to the effects of radiotherapy. This is challenging as it’s usually permanent, and even relatively low doses of radiotherapy may impair the function of the salivary glands. Saliva is important to aid speaking, swallowing and it plays a role in general oral and dental hygiene. It’s important to maintain a regular intake of water during and after treatment as well as attend regular dental appointments before and after the course of radiotherapy.
Completion of RT
Following completion of treatment, follow-up appointments should be scheduled, and follow-up blood tests and scans should be discussed. You may also need to be seen by the referring doctor again, depending on the case and on the treatment plan going forward.
Dr Maríza Tunmer is a specialist radiation oncologist working in private practice at the Wits University Donald Gordon Medical Centre in Parktown, Johannesburg.
Header image by Freepik