Radiation therapy for pancreatic cancer

Also known as radiotherapy, radiation therapy uses a controlled dose of radiation to kill cancer cells or injure them so they cannot multiply.The radiation is usually in the form of focused x-ray beams targeted at the cancer. Treatment is painless and carefully planned to do as little harm as possible to healthy body tissue near the cancer.

Chemoradiation

For stage 3 cancers that cannot be removed with surgery (locally advanced cancers), radiation therapy may be given with chemotherapy to slow the growth of the cancer. This is called chemoradiation. For cancers that are at a stage where they can be removed by surgery, chemoradiation may also be used before or after the surgery.

In chemoradiation, the radiation therapy is delivered over several treatments (called fractions). Each fraction delivers a small dose of radiation that adds up to the total treatment dose. Your doctor will let you know your treatment schedule. Many people have treatment as an outpatient once a day, Monday to Friday, for up to 6 weeks.

Each radiation therapy session takes 10–15 minutes. You will lie on a table under a machine called a linear accelerator that delivers radiation to the affected parts of your body. The machine does not touch you, but it may rotate around you to deliver radiation to the area with cancer from different angles. This allows the radiation to target the cancer more precisely and limits the radiation given to surrounding tissues.

Radiation therapy on its own

Radiation therapy may also be used on its own over shorter periods to relieve pancreatic cancer symptoms. For example, if a tumour is pressing on a nerve or another organ and causing pain or bleeding, a few doses of radiation therapy may shrink the tumour enough to relieve the symptoms.

SBRT

Stereotactic body radiation therapy (SBRT) is an emerging treatment for pancreatic cancer. It delivers a higher dose of radiation per treatment session over fewer treatment sessions than usual radiation therapy. SBRT is not standard practice for pancreatic cancer but may be a treatment option as part of a clinical trial at some cancer centres.

Linear accelerator (LINAC)

This is a general illustration of a LINAC. The machine used for your treatment may look different. A LINAC is large and is often kept in a separate room. An imaging device, such as a CT scan machine, is usually attached to the LINAC. This helps position you accurately on the couch so the radiation targets the correct area of your body.

Side effects of radiation therapy

Radiation therapy can cause side effects, which are mainly related to the area treated. For pancreatic cancer, the treatment is targeted at the abdomen.

Side effects of radiation therapy to the abdomen may include:

• tiredness
• nausea and vomiting
• diarrhoea
• poor appetite
• reflux (when stomach acid flows up into the oesophagus)
• skin irritation.

Most side effects start to improve a few weeks after treatment, but some can last longer or appear later. Late side effects are uncommon, but may include damage to the liver, kidneys, stomach or small bowel. Talk to your radiation oncologist or radiation oncology nurse about ways to manage these side effects.