A guide to radiotherapy

What is radi​otherapy?

Radiotherapy is the use of ionising​ radiation, usually high energy x-rays, to treat disease. Generally, radiotherapy is used to treat malignant disease (cancer). However, it is sometimes used to treat benign tumours and some other benign diseases. This guide will confine itself to the treatment of cancers and other malignant diseases with radiation.

Radiotherapy treatment is often fractionated, ie, given over a number of days. This allows large doses of radiation to be given whilst sparing normal tissue from too many side effects. Generally, radical treatments are given in more treatment fractions than palliative.

Staff involved

Clinical oncologist
Medical consultants qualified in the treatment of cancer using radiotherapy, chemotherapy and hormone therapy. They usually specialise in the treatment of particular cancers.

Therapeutic radiographer
Specialist qualified in the localisation and treatment of cancer using ionising radiation (as distinct from diagnostic radiographers who image patients for diagnosis). Therapeutic radiographers' levels of practice range from practitioner through to advanced, and to highly specialised consultant roles.

Support staff 
There are a large number of staff who support the radiotherapy service, which include clerks, secretarial and administrative staff, clinic helpers and assistant practitioners and support workers. They ensure the smooth running of the service and appropriate skill deployment.

Physicist / clinical scientist
These are physics graduates who are scientifically trained in the techniques for accurate measurement, assessment, optimal operation and development for the equipment used in radiotherapy delivery.

Clinical technologists
Trained in clinical physics to undertake and develop systems for patient immobilisation (mould room), production of patient treatment plans, routine QA, machine servicing and maintenance, plus engineering support.

Those employed in the production of patient plans for treatment are often called dosimetrists.

How important is radiotherapy in the treatment of cancer? 

Radiotherapy is a very important tool in the treatment of cancer. It is used as the main treatment for some cancers, when it is given with the aim of curing the cancer. This is sometimes referred to as radical radiotherapy.

It is sometimes given as well as surgery, to reduce the chance of the cancer relapsing: in these circumstances it is referred to as adjuvant radiotherapy. 

Radiotherapy is also very effective in relieving certain symptoms of cancer, for example pain from secondary tumours in bone. This is called palliative radiotherapy, where the aim is not to cure the cancer, but make the patient more comfortable/able to lead a more normal life.

The use of radiotherapy has, and continues to, expand due to better patient pathways, the role of multi-disciplinary team meetings and better integrated packages of patient treatment using the all-effective treatments available to us. As technology advances, more things become possible, and allow us to aim to cure and palliate more patients. For this reason, the role of, and need for, radiotherapy continues to expand year-on-year.

Surgery remains the most effective way of curing cancer. 49% of all patients cured of cancer are cured by surgery. Radiotherapy is the next most important method of curing cancer. 40% of all patients cured of cancer are cured by radiotherapy. Radiotherapy offers patients the choice of organ preservation and of avoiding disfiguring or damaging surgery: For example, instead of mastectomy for breast cancer or penile amputation for penile cancer, conservation radiotherapy can be given. Radiotherapy can also be used for the treatment of certain cancers of internal organs and allow patients to avoid major surgery and retain function, with little or no loss of chance of cure. Examples of this would include cancers of the larynx, prostate and bladder.

Chemotherapy is important in the treatment of cancer. However, only 11% of those cancers that are cured are cured by chemotherapy. The majority of childhood cancers are cured by chemotherapy, which is also the mainstay of treatment for lymphomas and leukaemias. Very few adult solid tumours can be cured by chemotherapy. Testicular germ cell cancer and choricardcinomas are reliably chemocurable. However, they account for only a small minority of adult cancers.

Chemotherapy is sometimes given after potentially curative treatment (surgery +/or radiotherapy) to reduce the risk of relapse. This is called adjuvant chemotherapy. It produces modest (<10%) improvements in survival rates for some cancers, such as breast cancer and colorectal cancer. 

Chemotherapy may also be given simultaneously with radiotherapy (radiochemotherapy or chemoradiotherapy) to enhance the effect of radiotherapy. This is now standard treatment for some cancers, such as those of the oesophagus or uterine cervix. It is likely to be used for more cancers as the results of clinical trials become viable.

Hormones of various sorts are used to treat a number of cancers, notable breast and prostate. They may be used to palliate advanced disease, when they also significantly improve survival, and also as an adjunct to the treatment of early disease.

Increasingly, radiotherapy is given as part of a package of care/treatment, consisting of some or all the elements mentioned above, with increasingly good outcomes for patients.

What sorts of radiotherapy are there?

Radiation can be used to treat cancer in a number of ways:

Brachytherapy
This involves the placing of sealed radiation sources in or near a tumour. This method allows the delivery of high doses of radiation to the tumour target. Because the dose of radiation falls rapidly with distance from the source, normal tissues may be spared high dosed. Brachytherapy may involve the permanent placement of radioactive sources or they may be inserted for a time and then removed - a temporary brachytherapy implant.

Permanent brachytherapy is most commonly used to treat early prostate cancer, when very small capsules containing radioactive iodine (iodine seeds) are implanted into the prostate.

Temporary implants may sometimes be performed by inserting radioactive wires directly into a tumour. This technique is used, for example to treat early tongue cancer, when specially shaped ‘hairpins’ are inserted into the tongue under general anaesthetic. More usually a tube or a series of tubes is positioned with the tumour or within a hollow organ (such as the uterus or the oesophagus) and the radioactive material is loaded into the tube after its position has been checked. This may be done by hand (manual afterloading) or a machine may be used to move the radioactive source into and out of the tube (remote afterloading).

Teletherapy
Most patients are treated with external beam radiotherapy, using a machine called a linear accelerator. A beam of radiation is generated and directed at the cancer, at the same time avoiding, as far as possible, normal tissues. Several beams may be combined to increase the dose to the tumour and reduce the dose to normal tissues. External beam radiotherapy is sometimes referred to as teletherapy. 

The following are all kinds of external beam radiotherapy:

• Conformal radiotherapy (CRT): The beams of radiation directed at the patient are shaped (conformed) to match the shape of area that needs to be treated. This allows sparing of normal tissues and higher doses to be given to improve chances of cure/control. Beams are shaped using shielding devices, either internal (multi-leaf collimators) or external (shielding blocks) to the treatment machine.
• Intensity modulated radiotherapy (IMRT): The beams of radiation are formed around the area that needs to be treated by varying (modulating) their strength (intensity) to achieve the desired dose and coverage. This form of treatment is different in that it tends to be given in one sequence (not a number of fields), with field size, shape and angle varying throughout the sequence. This type of treatment needs specialised treatment planning and delivery systems.
• Stereotactic radiotherapy (STR): Multiple fields of radiotherapy that are directed at a very small area, needing very accurate localisation, using a dedicated positional frame, worn by the patient, to achieve reproducible daily accuracy. This form of treatment is most commonly used for treating small areas of the brain. Again, specialised equipment is needed to plan and deliver this type of treatment.
• Stereotactic radiosurgery (SRS): Technique similar to above, but treatment is focused with many more very small beams and the patient is attached to the positional headframe. This can be done using a linear accelerator, but requires accessory equipment and can affect throughput due to change-over time required. More often delivered using a gamma knife, a dedicated piece of equipment using many small radioactive sources.
• Total body irradiation (TBI): Undertaken as part of induction for bone marrow transplant to kill off patients residual bone marrow before replacement is introduced. This technique is usually undertaken in large regional radiotherapy centres with attached bone marrow transplant units and requires expertise in TBI dosimetry.
• Total skin electron irradiation (TSEI): Technique which uses electron beams to irradiate the entire skin surface of the patient, usually for the treatment of skin lymphomas, and requires dedicated expertise in electron beam dosimetry and monitoring.
• Continuous hyperfractionated accelerated radiotherapy (CHART): Treatment regime which accelerates the rate at which the radiotherapy is given (between two and three times daily) and eliminates gaps (ie, patients continue to be treated over the weekend). One of the few radiotherapy trials undertaken to prove positive survival advantages for lung cancer patients.
• Superficial x-ray therapy (SXT): Very low energy x-rays, usually below 120 Kilovolts, used to treat small skin cancers. Larger skin cancers are usually treated with electron beams (high energy megavoltage beams generated by linear accelerators). The choice to treat skin cancers with surgery or radiotherapy is related to position of the lesion, the general condition of the patient and their preferences.
• Deep x-ray therapy (DXT): Low energy X-rays, usually in the 220 – 330 Kilovoltage range, used to treat superficial lumps, bumps and metastases, such as ribs, etc.

The radiotherapy p​rocess

Treatment planning

The delivery of radiotherapy is a complex process and careful preparation is necessary before treatment can begin. Often, something may be used to help the patient maintain their position during treatment planning and delivery. This may be a simple device, such as a shaped cushion. It might be a more complex support, which can be used for a number of patients but adjusted for each, or an individual immobilisation device may be made for a particular patient. 

Sometimes these immobilisation devices are made of a plastic material, which softens with gentle heat and can be moulded to fit the body. Sometimes a plaster of Paris impression is taken of the part of the body to be immobilised and the plastic material is moulded on this. These processes are carried out in a mould room.

Once any pre-planning preparation has been completed, the planning process can begin. Occasionally, for example with skin cancers that can easily be seen, the oncologist is able to mark the area to be treated directly on the patient. More usually, it is necessary to define a target volume within the patient. 

The oncologist will have information about the size, shape and location of the tumour from a variety of sources. This may include information from colleagues, if there had been an operation or an endoscopy, together with information from x-rays and scans of various sorts. The oncologist will use this information to define the size, shape and location of the tumour within the patient. 

Increasingly, volume definition is carried out using a CT scan performed expressly for this purpose (a planning scan). Sometimes the oncologist will work with x-ray images taken on a special x-ray machine, called a simulator. The simulator can be adjusted to produce x-rays of a known magnification and also to produce x-ray beams that match the dimensions of those that will be used to treat the patient. This process is called localisation. 

Once the oncologist has decided on the target volume and also on the position of those organs and structures to be avoided completely or to receive only a small dose of radiation, a dosimetrist will work to produce a treatment plan. They will decide on the size, shape, position and direction of the treatment beams that will work best for that particular tumour, that is that will allow the delivery of a high and uniform dose of radiation to the tumour, while keeping the dose to normal tissues to a minimum. This may require several attempts, particularly in difficult circumstances, and will be independently checked. Treatment may be delivered in a number of phases (up to three for some head and neck cancer patients), with each phase requiring a separate plan as the volume needing treatment changes. 

A treatment plan is produced using a treatment-planning computer. This will show the target volume and also any organs at risk. It will also show the distribution of radiation within the tumour and the normal tissues. The oncologist will review the treatment plan and approve it if it is satisfactory. He will then write a radiotherapy prescription. This will specify the total dose of radiation to be given, the number of beams (fields) to be used, the frequency of treatment (daily, twice daily, alternate days, etc), the number of treatments (fractions) to be given and the overall treatment time (the number of days or weeks from the start of the course of the treatment to the end).

For historical reasons, most radiotherapy is given daily, Monday to Friday, with most departments operating a standard, outpatient working day (9am-5pm).

Sometimes the patient will be taken back to the simulator to confirm that the treatment beams are correctly shaped and positioned before their course of treatment starts. This process is called verification. In some departments, the process of verification is carried out on the treatment machine using special imaging equipment, often called an electronic portal imaging device (EPID). This enables a true verification of the treatment to be delivered to the patient, as they will actually be on the treatment machine in the required position, but it can reduce machine throughput.

Before treatment can start

The information needed to treat a patient with radiotherapy needs to be exact and reproducible on a daily basis. Before treatment can start all the data needed – images, treatment plan, treatment prescription, position, set-up instructions, etc, needs to be input into the treatment delivery system of the treatment machine and independently checked.

All modern radiotherapy departments use these systems, called record and verify systems, to reduce daily errors (imperative when dealing with high energy, potentially highly damaging doses of radiation). Modern systems allow data to be transferred electronically, directly from planning and simulation systems – commonly known as DICOM transfer. This facility reduces data transcription which is a major source of routine error.

Where DICOM transfer of data is not available or activated, therapy radiographers manually input the data required. For some patients who are simply planned, they will additionally perform (and independently check) a calculation of the daily radiation to be given. All data, whether manually input or DICOM transferred is independently reviewed before treatment is given.

The tasks involved in preparing all aspects of the patients pre-treatment process all require a high level of understanding and concentration to ensure accuracy and efficiency, and so should ideally be performed in a quiet uninterrupted environment.

Treatment delivery

Treatment is delivered by therapy radiography staff, working in teams, to enable the efficient and accurate set-up of the patient, and reduce human errors in the process. Daily treatment involves the correct identification of the patient, accurately reproducing the treatment position by manipulating the patient and any associated aids, correcting for anomalies and providing advice and support.

Monitoring and supporting the physical and emotional well-being of patients undergoing treatment involves ensuring patients are aware of the likely side-effects of treatment, actions which can be taken to avoid or reduce their impact, and strategies for coping with them – physically and emotionally, which can also include aspects of living with their disease. 

Patients are usually seen regularly when on treatment, to check their progress and make sure their needs are being met. In some centres this is undertaken by their Oncologist (or a member of their team), whereas in others therapeutic radiographers and/or specialist nurses perform this role, including prescribing appropriate medication and recommending changes to care.

At completion of treatment, the treatment is summarised for communication to others involved in the patients care. The therapy radiography staff ensure that the patient is appropriately discharged, ie, aware of the next steps for them and that they can manage any side effects they have or are likely to develop.

Supporting systems

Radiotherapy equipment at all process stages is complex and expensive. It requires regular routine maintenance and quality assurance to maintain the high levels of pin-point accuracy on which treatment planning and delivery are based. 

Specialist, highly trained staff are required to undertake these tasks – physicists and technicians.

Technicians are required to routinely maintain and repair the mechanical, electronic and software systems of modern machines. They must be available to respond to any unforeseen breakdown/fault to ensure patient safety and allow capacity to be maintained. Periods of time when equipment is out of clinical use is commonly called downtime. This refers to any period (routine servicing, repair or breakdown) when that equipment is out of use. Any downtime within scheduled hours of use reduces equipment capacity. Downtime can be reduced by scheduling planned servicing out of scheduled clinical hours, or removed by ensuring available spare capacity.

Physicists are key to ensuring that machines are accurately calibrated to deliver the radiation dose intended and that this level of accuracy is maintained. They play a key role in standards required for equipment for clinical use. They must be available to advise promptly on dosimetry issues that arise during the planning and treatment of patients.

In order to be able to deliver radiotherapy to the large variety and numbers of patients on a daily basis, track patients through the system / process and ensure optimum utilisation, most departments use a patient scheduling system. These systems allow complex patient pathways to be coordinated and flow smoothly. Advanced systems link with Trust PAS, radiotherapy equipment and R+V systems, which reduces data inputting and allow DICOM transfer and electronic updating.

Some patient scheduling systems are part of a wider electronic radiotherapy management system. The advantage of these systems is that they provide standard reporting tools which allow services to analyse their workload and performance from data already input, ie at no additional or separate effort. Once appropriately coded, they can provide data on waiting times, target compliance, HRG / caseload mix, demand and utilisation / activity levels. This information is key to enabling service optimisation and planning.

How do I know how my local radiotherapy service compares with others?

There are number of national measures that radiotherapy services can be measured against:

Cancer Waiting times are 31 days from decision to treat to first definitive treatment and 62 days from urgent GP referral to first definitive treatment.

Decision to treat: Date the patient agrees with the oncologist to undergo a course of radiotherapy. If the booking/referral form is filled out at this point, it would be suitable for monitoring purposes. Problems arise when measuring waiting times for patients who have a series of adjuvant treatments of which radiotherapy is only one and not the first. Proposals have been made to use 'ready to start' for patients undergoing multiple sequential treatments.

First definitive treatment: This is the first treatment that a patient has for their cancer. For example, a patient who undergoes pre-operative radiotherapy, their radiotherapy is counted as their first definitive treatment. However, for a patient who has chemotherapy before starting radiotherapy, chemotherapy is their first definitive treatment.

Cancer standards

The Cancer Standards (against which all networks are being peer reviewed against during 2005 and 2006) contain 63 standards relating to delivering an acceptable radiotherapy service, including equipment and staffing levels.

These include:

• Urgent patients treated within 24 hours (good practice);
• Urgent patients treated within 48 hours (acceptable);
• Palliative patients treated within 48 hours (good practice);
• Palliative patients treated within two weeks (acceptable);
• Radical patients treated within two weeks (good practice);
• Radical patients treated within four weeks (acceptable).

The Radiotherapy Episode Statistics (RES) project, currently being undertaken by Brian Cottiers Cancer analysis team, provides individual service and benchmark data for all aspects of radiotherapy activity and waiting times.

If your service is not meeting any of the national standards, they should be able, using service improvement tools and data, to identify their bottlenecks, have modelled various options and have a plan to address the situation. This would include service expansion and/or development. 

Further information is available here

Response (to treatment)
An end point used as a measure of the effectiveness of a treatment. The World Health Organisation (WHO) definition of complete response is that any measurable disease becomes undetectable, and remains so for four consecutive weeks; a partial response is that tumour(s) shrink to the extent that the product of tow diameters at right angle is reduced by 50% and that this reduction is maintained for four consecutive weeks. This measure is mostly used in chemotherapy.