Radiation therapy for lung cancer

When is radiation therapy used?

Also known as radiotherapy, radiation therapy uses radiation to target and kill cancer cells. This reduces the risk of the cancer growing or spreading. It uses advanced technology to focus the radiation on the cancer and avoid the normal parts of the body. You may be given radiation therapy on its own, or after surgery or chemotherapy, or at the same time as chemotherapy (called chemoradiation). When you have it depends on the stage of the cancer.

Radiation therapy may be recommended to treat the primary tumour in the lung:

• if you are unable to have surgery for stage 1 lung cancer
• if you chose not to have surgery
• where a surgery is not able to be safely done to treat locally advanced (stage 3) NSCLC, or to treat limited-disease SCLC
• after surgery, if there is a risk of microscopic cancer cells left behind.

You may be offered radiation therapy as palliative treatment, to control the primary tumour in the lung or areas where the tumour has spread to, with the aim of relieving pain, breathlessness or other symptoms.

For lung cancer, radiation is usually delivered in the form of x-ray beams from a machine outside the body called a linear accelerator. This is known as external beam radiation therapy (EBRT) and can be done as standard EBRT or stereotactic radiation therapy (see below).

Standard EBRT 

This is usually given once a day, Monday to Friday; each daily treatment lasts for a few minutes. How many treatments you need will depend on the aim of the treatment. To control symptoms, it’s usually 1–2 weeks. Longer-term control is usually for 3–6 weeks.

Stereotactic radiation therapy

Also called stereotactic body radiation therapy (SBRT) or stereotactic ablative body radiation (SABR), this can be given as a single dose or a number of doses. It targets a localised tumour with a very high dose of radiation. SBRT cannot be used safely if tumours are close to other organs, such as the windpipe.

How radiation is done

External beam radiation uses a machine that gives high-dose radiation beams from different angles to precisely target the tumour.

Planning radiation therapy

Before treatment starts, you will have a planning session at the radiation therapy centre to work out the dose and position of the beams. During this session, you will have a CT scan to determine the area to be treated, and small marks will be put on your skin so the radiation therapists ensure your body is in the same position for every treatment. You may have a 4-dimensional CT scan to record any movement of the cancer as you breathe. You may also be shown some breathing exercises to help your breathing stay as regular as possible.

Having radiation therapy

Each treatment day, a radiation therapist will help you lie in the position decided at the planning session. You will have an x-ray to check that the correct area is being treated. When the treatment is being delivered, you will be alone in the room, but the radiation therapists will be able to hear you and talk to you from the monitoring area as there are speakers and a microphone in the room. The radiation treatment itself takes only a few minutes, but a session may last about 20 minutes, depending on how complex the set-up process is.

Side effects of radiation therapy

Radiation therapy itself is painless, but it can affect some tissues and organs of the body. You may experience some side effects during or after radiation therapy, depending on the dose, the number of treatments and the part of the chest treated. Most side effects are temporary and improve a few weeks after treatment.