Introduction

Radiotherapy has been a key treatment for cancer for over a century and although the fundamental principles of treatment have not changed, the method of delivery and the treatment techniques have changed considerably. Most patients diagnosed with cancer undergoing radiotherapy will receive their treatment as an outpatient, so you may meet them in the community setting or in an outpatient unit, or on a ward if they are admitted for a treatment-related problem or other medical condition. Radiotherapy remains misunderstood by patients and it is often feared due to association with radiation disasters and misuse. It is important while on a cancer/palliative placement that you make the most of the opportunity to understand this treatment; arrange an insight visit to the radiotherapy department to observe the equipment and to understand the complexity of planning radiotherapy and to appreciate the experience of patients.

After surgery, radiotherapy is the most effective curative treatment for cancer (Burnet et al 2000). Approximately 50% of patients in the UK will receive radiotherapy. Unlike the treatments discussed in previous chapters that are given systemically, the value of radiotherapy is in the local management of cancer. The success of radiotherapy is dependent on how bulky the tumour is, how sensitive the tissues are to radiation and the location of the tumour.

Radiation is a natural part of the electromagnetic spectrum. At one end of the electromagnetic spectrum are radio waves which have low energy and bounce around us; at the other end of the spectrum, X-rays, beta and gamma rays are highly energised and can penetrate into the body, causing ionisation. Ionisation is where the atoms within the cell are altered by the radiation. Atoms are electrical in nature. When they come into contact with radiation, the highly energised waves from the radiation cause an orbiting electron to be dislodged and join an adjacent atom which is said to be ionised (Fig. 13.1).

Fig 13.1 Ionisation of atoms

Whether an atom has lost or gained an electron, the atom becomes unstable and the cell DNA becomes damanged (especially when the cell is dividing), causing the cell to die. Similar to cytotoxic drugs, radiotherapy will damage and kill healthy cells as well as cancer cells. Normal cells have the ability to repair and replace themselves when they are damaged though.

X-rays, beta and gamma rays have the right amount of energy to produce ionisation in atoms, which takes place as radiation passes through tissue. Different tissues have different levels of sensitivity to radiation. This will affect the success of the treatment but also restricts the dose that can be given.

Radiotherapy is measured in Grays (Gy), the amount of radiation absorbed by tissues (1   Gy = 1 joule of energy absorbed per Kg of tissue). Cancers that are radio-sensitive (lymphomas, germ cell cancers) are given lower doses (20–45   Gy), while those that are radio-resistant (gliomas, prostate, adenocarcinomas) are given higher doses (60–70   Gy).

External beam radiation is the commonest type of radiation treatment. It is given in the outpatient setting using beams of radiation that are artificially made by accelerating X-rays using a machine called a linear accelerator (Linac).

There are four principles (‘four Rs’) that support our understanding of how radiotherapy works:

Careful planning of radiotherapy is essential to maximise the effects and minimise the damage to sensitive surrounding tissues and this may take time and delay treatment. X-rays and magnetic resonance imaging (MRI) scans are used to identify the location of the cancer. These scans are loaded into a planning computer to ascertain the shape and size of the treatment field. To minimise the damage to sensitive structures and tissues, the smallest area possible is treated. Shields and moulds are used to shape the beams and control the depth of penetration. A mask may be made if an area of the body needs to be immobilised to ensure precision, such as the head and neck. The dose and number of fractions are calculated and a machine called a simulator (a diagnostic X-ray machine) is used to give a dry run to check the accuracy and to make any adjustments. The information from the simulator is then used by the radiographer to deliver the radiotherapy exactly as planned.

Seeing this for yourself will help you to reassure patients who are undergoing radiotherapy that you might meet while on another placement.

External beam radiotherapy is particularly good in the management of symptoms. Because of the way radiation works, the cells do not immediately die and the treatment may initially cause exacerbation of symptoms, which may increase distress and anxiety. Many patients experience bone pain (often caused by bone metastases). Bone pain is often unresponsive to pharmaceutical drugs but generally is responsive to radiotherapy. Radiotherapy to the site(s) of the cancer in the bone will kill the cancer cells and stimulate new bone growth. It takes several days, and up to 2 weeks before the full benefit is achieved and pain is reduced. During this time, the level of analgesia should be maintained and the patient should be informed that there will be a delayed response.

Nerve and visceral pain can also be difficult to manage as the cancer invades, compresses and distorts organs. Radiotherapy reduces the size of the cancer and relieves pressure and inflammation.

Hepatic pain is very sensitive to radiotherapy which can relieve jaundice by reducing hepatobiliary obstruction.

Brain metastases respond well to radiotherapy and 80% of patients with cerebral metastases experience symptomatic relief, with a reduction in headaches, seizures and blurred vision. Again, it takes time for the treatment to work and the average response time is 10 weeks. This has obvious implications for patients with a short life expectancy. Patients often require hospitalisation during or post-treatment due to increased symptoms initially, such as seizures, headaches, increased cranial pressure, etc. The use of steroids can help alievate this exacerbation of symptoms.

Bleeding such as haemoptysis, fistulas, ulcerated and fungating wounds (caused by cancer breaking through the skin) can also be managed by radiotherapy, to reduce discomfort and stem bleeding. In addition, improvements can be achieved in breathlessness and dysphagia. Spinal cord compression requires urgent radiotherapy to reduce the pressure on the spinal cord. By killing the cancer cells and allowing bone reformation, some motor function may be regained. This is dependent on the degree of damage caused initially.

Where radiotherapy is used to palliatiate symptoms rather than as a definitive treatment, the effects will only last until the cancer grows. This condition is explained more fully in Chapter 15.

Other radiation treatments

Radiation can also be used directly inside the body. These treatments are referred to as brachytherapy (sealed) and unsealed sources. Caesium 137, a sealed radioactive isotope, can be placed inside the body. This is often used for gynaecological cancers like endometrial or cervical cancer. Usually the patient will have surgery and a course of external beam radiotherapy and will then be admitted for the internal radiation. A set of applicators (either two or three) are inserted vaginally and packed into place under a general anaesthetic and a urinary catheter is inserted. The patient will then have their treatment planned using the simulator (mentioned above). They are then returned to the ward and placed in a lead-lined room. The applicators are connected to tubes that are attached to a machine known as a selectron. When the machine is switched on, radioactive caesium pellets travel down the tubes and into the applicators inside the patient. These pellets deliver radiation directly to the area where the cancer is. The patient is nursed flat and must not move in case of dislodging the applicators. They will require postoperative care and regular pain management. As and when the patient needs assistance, the selectron machine can be turned off and the radioactive pellets returned into a safe. This means it is safe for nurses to attend to the patient without coming into contact with the radiation. Up until recently, patients received their selectron treatment as an inpatient and were attached to the machine for between 10 and 20 hours, however an increasing number of cancer centres have introduced this treatment as a day case. The procedure, known as low-dose rate selectron, is similar to the inpatient treatment, but the patient receives a short anaesthetic, the applicators are left in place and the patient will receive treatment over a few days as a day case.

An example of a sealed radioactive treatment is iridium wires which are inserted into the skin and tissues under a general anaesthetic. These wires are used to treat anal, vaginal and urethral cancers. The risk to healthcare professionals is much higher with this treatment as the radiation cannot be temporarily removed and the patient will be radioactive for the duration of the treatment. Similarly, iodine 131 is an unsealed source which is given as an oral capsule or liquid. When consumed it is absorbed into the thyroid gland and cancer cells in the thyroid will be killed. This is used in conjunction with, or instead of, a thyroidectomy. Because the iodine 131 is given orally, these patients will stay radioactive until the radiation starts to degrade – this may be several weeks. Patients who have had iodine 131 are required to stay in a lead-lined room for between 4 and 7 days (depending on the time taken to degrade the radioactivity). During their admission, patients are highly radioactive, therefore they should require minimal assistance with their activities of daily living and self-administer their medications, minimising contact with healthcare professionals. As a student, you should not enter a patient’s room if they have received either iodine 131 or iridium wires. This is discussed in Chapter 7 under health and safety issues.

While undergoing iodine 131 treatment, the patient will only be allowed to use disposable crockery and cutlery. All surfaces are covered in a plastic film to minimise radiation contamination from the patient’s sweat and the medical team will closely monitor the radiation levels.

It can be very lonely being isolated for such a time, therefore patients should be advised to bring plenty of activities such as books, puzzles, DVDs, music, games, laptops, etc. However, they need to be aware that everything they bring in with them will be monitored for radioactivity. If the levels of radiation in the patient’s belongings are not at a safe level at the time of discharge, the items are retained by the hospital and placed in the radiotherapy ‘bunker’ (essentially a lead-lined store room) until the radiation has degraded, at which time they are returned to the patient. The patient will also be radioactive on discharge. Although the radioactive levels will have reduced to a safe level for them to return home, as a precaution they should avoid contact with children and pregnant women. They should use separate crockery and cutlery and sleep in a different room to their partner for a few weeks after treatment.

The impact of undergoing radiotherapy

Patients often are frightened or misunderstand what radiotherapy treatment actually is. This is often based on catastrophic events such as the World War Two atomic bombings of the Japanese cities of Nagasaki and Hiroshima and the nuclear power disasters in Chernobyl in the Ukraine in 1986 and Japan in 2011. Because of the technical nature of the treatment, patients and healthcare professionals often lack knowledge and understanding of how radiotherapy works. It is an abstract concept compared to surgical treatment where the cancer is physically removed or cytotoxic drugs are seen to enter the body. Radiotherapy is invisible. Peck and Boland (1977) demonstrated that approximately 60% of patients feel unprepared for treatment. Although this research is old, the figure is still relevant today. Information is required to outline what is involved in radiotherapy planning; how the treatment works; what to expect while in the radiotherapy department; the practicalities, such as parking; the duration of each treatment; what the likely side effects are and how these can be prevented; who to tell if a toxicity develops, etc. (Halkett et al 2010).

Because of the location of cancer centres with a radiotherapy department, patients might be required to travel long distances or they may be required to stay overnight.

The side effects of radiotherapy are varied and depend on the site of treatment. Severe toxicities may limit the dose that can be given, prolonging treatment time and the overall efficacy of treatment. However, the frequency and severity of radiotherapy side effects has reduced significantly due to developments in planning and delivery.

Like cytotoxic therapy, radiotherapy kills cells that are frequently dividing, so any normal cell that is active in the cell cycle and comes in contact with the radiation will potentially be damaged or killed. As all external radiotherapy beams have to enter the body through the skin, adverse skin reactions are common. The severity of the damage will depend on the dose; the number of fractions; and site of treatment (skin folds and areas of friction are more likely to increase the risk of a skin reaction). Exposure to sunlight will increase the risk of damage as will mechanical irritation such as clothes rubbing, shaving, etc. (Porock et al 2004). Other factors will influence how quickly and easily the body repairs the damage to the skin, such as age (the older we get, the slower the body repairs damage) and increased body weight (reduces healing, reduces blood supply, increased skin folds, friction and moisture).

Skin radiation reactions are often called ‘radiation burns’. This is incorrect as the reaction is a repeated insult and is very different in nature to a normal burn.

To minimise radiation skin reaction, patients should be advised to wash their skin gently with mild soap and warm water; shaving the area of treatment should be avoided and clothing should be made from natural fibres that do not rub. When assisting a patient undergoing radiotherapy with their hygiene needs in an inpatient setting, you should also follow this advice. Patients should have their skin assessed throughout and after treatment to identify reaction and for prompt intervention (NHS Quality Improvement Scotland 2004). Eighty per cent of patients undergoing radiotherapy experience erythema, a redness and slight inflammation of the site, which occurs approximately 10–14 days after the first fraction. This coincides with the damaged basal layers migrating to the upper layers of the skin. The skin compensates by increasing cell division to replace the damaged cells. The new cells are immature and are more easily damaged. If the new cells are produced quicker than the old ones are shed, then dry desquamation develops; this looks like dry, flaky, itchy skin. If the old cells are shed before the new ones can reach the top, then the thin epidermal layer is easily eroded; this is known as moist desquamation. Moist desquamation is more likely to develop in skin folds like under the breast, groin and axilla. When the skin breaks down, there is a high infection risk and the wound must be managed carefully to avoid further damage so that healing is promoted (MacBride et al 2008).

Another commonly reported general side effect is extreme fatigue. This tends to increase over the period of treatment. It is estimated that between 30% and 80% of patients undergoing radiotherapy will experience fatigue. This range is so wide, reflecting the subjective nature of the symptom and the difficulty in measuring fatigue (Jereczek-Fossa et al 2002). It is not clear why radiotherapy causes fatigue. It may be caused by travelling to and from the hospital daily and other side effects like loss of sleep, and the effort of the continual renewal of damaged cells.

As well as the general side effects, there are usually a number of site-specific toxicities depending on the site of the radiotherapy (Table 13.1).

Table 13.1 Site-specific radiotherapy side effects

The side effects of radiotherapy take a while to develop but last for a long time, often months after the completion of treatment. This is due to the indirect action of the treatment. The side effects may be temporary or permanent – either way, the majority of patients’ functioning and quality of life are affected in some way. Knowing what toxicities to expect is important in order for prompt intervention. However, patients may not recognise the cause of the symptom they are experiencing and others are reluctant to report problems, in fear that treatment may be reduced or withdrawn.