What is external radiotherapy?

External radiotherapy is the use of high-energy rays, such as x-rays, to treat tumours using a machine called linear accelerator. This treatment is used to cure some types of cancer (definitive radiotherapy) or to relieve symptoms (palliative radiotherapy). Radiotherapy may be used as a sole treatment or in combination with other treatments such as surgery, chemotherapy, hormone therapy or immunotherapy.

How does it work?

Radiotherapy works by damaging the DNA of cancer cells in the target area. Some normal cells in the area could also be damaged by the treatment, however they have the capability to recover from one session to the next, while cancer cells cannot repair themselves. This is the reason why the radiotherapy is usually delivered in multiple sessions.

What is the radiotherapy plan?

It is conducted by the medical physicists using a computerised treatment planning system. The radiotherapy plan defines the energy and the shape of the beams which should be generated by the linear accelerators to cover adequately the target volume while sparing the surrounding healthy tissue. The data of the treatment plan are then transferred to the linear accelerators, which are operated based on a specific plan.

Consultation

A consultation with your radiation oncologist is the first step in seeking radiation therapy. Here you will have the chance to ask any question regarding the procedure, risks and benefits of your treatment. The consultation appointment usually lasts one hour, during which the patient’s medical history, medication, previous test results and current condition will be discussed. Additionally, the doctor might perform a physical examination.

Planning CT appointment

Most radiotherapy treatments require a CT scan to create a plan. The part of your body that is to be treated will be scanned. The radiotherapy staff will position you in the correct position for the scan. This will position will be the same for your treatment, thus it is very important to feel comfortable. Then, the radiographers may make a small permanent mark (like a tattoo) on your skin. These marks make sure the same area is treated every day. In some cases, mostly when stereotactic radiotherapy is planned, a four-dimensional CT (4D-CT) is performed. During this CT scan the patient’s breathing motion is monitored and the respiration cycles are recorded as a waveform with which each individual CT slice is correlated. This enables the generation of an internal target volume by taking into consideration the tumour variations in the position due to respiration. Then, the treatment fields are adapted according to the position of the target throughout the respiratory cycle.

Having external radiotherapy

During the treatment you will need to stay still throughout the whole process. Each treatment session will only last 10 to 15 minutes. Once you are in the right position you will be left alone in the treatment room for the treatment to start. However, there are CCTV cameras inside the room from which the radiographers watch you carefully. You cannot feel radiotherapy when it is actually given. The machine will be going around your body to deliver treatment from different directions. The treatments are held daily on weekdays, except bank holidays. The radiographers will do their best to give you an appointment that suits your schedule.

General side effects of radiotherapy

The side effects of radiotherapy vary, depending on the area irradiated. They can be divided into the acute ones, which might appear during the course of radiotherapy, can be managed with simple advices or with drugs and usually wear off within few days or weeks after radiotherapy and into the delayed ones, which might appear months or years after radiotherapy, their management is more difficult and might persist for a longer time. Your doctor will advise you about the potential side-effects and the ways to reduce and cope with them.

Number of treatment sessions

The number of treatment sessions depends on the radiotherapy plan chosen by your oncologist and the purpose of the treatment (definitive or palliative). For most treatments the radiation course lasts for 4 to 6 weeks. Often the duration is shorter, usually 2 to 3 three weeks. There are also radiotherapy regimes that only last for several days. It is important not to miss or delay treatments because it can lessen the radiation effect.

Follow up

When radiotherapy is completed, radiotherapists will give you information about your recovery and how to cope with any side effects. Remember that the full effect of radiotherapy usually occurs after 4 to 6 weeks, therefore any side effects you had experience may get worse until eventually get better.

You should contact the radiotherapy department if you notice any new symptoms or if you have any concerns. Your oncologist will arrange your follow up appointments where you will have the chance to discuss any problems or worries which may have come up.

What is brachytherapy?

It is a method of radiotherapy in which, however, the tumor-target is irradiated internally, without affecting healthy tissues. This allows high doses to be administered in order to achieve local control of the disease.

How is the treatment carried out?

Depending on the patients’ clinical condition, an imaging test will need to be done in advance in order to help your doctor assess the precise anatomy of the tumor and the area in which it is located in relation to the surrounding organs.
You will then be taken to the brachytherapy operating theater, where you will be given epidural or general anesthesia. Then, with the assistance of the medical physicist, intraocular catheters will be placed by the specialist doctor into specific positions, which have been determined with almost absolute accuracy. Once the needles are in the designated area of the tumor, radiation will be administered directly into that area. followed by irradiation. The number of catheters depends on the size of the tumor, and the stage of the disease, and the time required for the radiotherapy. For example, irradiation of prostate cancer normally takes about 15 minutes.

Once everything is set-up as described previously, and the radiation is to be administered, the brachytherapy team members will leave the operating room, but they will monitor the patient from internal cameras, and will also be able to communicate verbally. You can talk to them, tell them how you feel. Always have in mind that treatment can be stopped at any time, and start again when you feel better. But be assured that during the whole procedure there is no pain, and you cannot feel, see or hear the controlled amounts of radiation entering your body, exactly at the tumor-target.

When the procedure is completed, the intraocular catheters are removed and you are transferred to the intensive care unit for full resuscitation. Depending on the treatment and your clinical situation, doctor’s will determine if and how long you will need to stay under observation at the Patient Ward.