Radiation therapy for pancreatic cancer

Radiation therapy uses high-energy rays or particles to destroy cancer cells.

Some people with pancreatic cancer have radiation therapy. Your healthcare team will use what they know about the cancer and about your health to plan the type and amount of radiation, and when and how it is given.

You may have radiation therapy to:

• treat unresectable pancreatic cancer
• shrink a tumour before other treatments such as surgery or chemotherapy (called neoadjuvant therapy)
• destroy cancer cells left behind after surgery or chemotherapy to reduce the risk that the cancer will come back (recur) (called adjuvant therapy)
• relieve pain or control the symptoms of advanced or metastatic pancreatic cancer (called palliative therapy)

Radiation therapy for pancreatic cancer may be given on its own or during the same time period as chemotherapy( called chemoradiation). Some chemotherapy drugs can help make radiation work better by making cancer cells more sensitive to radiation. Combining chemotherapy and radiation therapy can be more effective than either treatment on its own.

During external radiation therapy (also called external beam radiation therapy), a machine directs radiation through the skin to the tumour and some of the tissue around it. Standard external radiation therapy is usually given once a day, 5 times a week for up to 6 weeks.

Doctors may also use the following external radiation techniques to accurately target the area to be treated and spare as much surrounding normal tissue as possible.

Stereotactic body radiation therapy (SBRT) i s a type of external radiation therapy that delivers targeted high doses of radiation to tumours in hard-to-reach areas in fewer sessions. It is also called stereotactic ablative radiation therapy (SABR). The majority of SBRT is delivered by modern linear accelerators but can also be delivered with a CyberKnife unit. It creates many beams of radiation from different angles that meet at the tumour. The tumour receives a high dose of radiation from the combined beams while surrounding tissue receives a low dose from the individual beams. This lowers the effects of radiation on healthy tissue surrounding the tumour. SBRT is given in fewer treatments than standard external radiation therapy.

Image-guided radiation therapy (IGRT) uses imaging mounted on the linear accelerator to improve the accuracy of radiation therapy. Repeated CT, MRI or PET scans are done before and during treatment and processed by computers to show changes in tumour size and location compared to the last treatment. This allows the radiation treatment team to adjust the radiation dose or your position on the table to increase the accuracy of the treatment. IGRT can lessen the amount of tissue treated and the total dose of radiation received by normal tissue. The special equipment needed to give IGRT isn't available at all treatment centres or hospitals.

Proton therapy uses protons (positively charged particles) to treat cancer. It may also be called proton beam therapy. Proton therapy uses proton beams instead of x-ray beams. Protons release more energy after reaching a certain distance and then stop, while x-ray beams release energy before and after they hit their target. So protons cause less damage to tissues they pass through on the way to their target. Proton therapy causes the least amount of damage to nearby normal tissues. A machine called a synchrotron or cyclotron produces the protons. These machines are not available at most treatment centres in Canada, and you may have to travel to the US to receive this treatment.

During radiation therapy, your healthcare team protects healthy cells in the treatment area as much as possible. Side effects of radiation therapy will depend mainly on the size of the area being treated, the specific area or organs being treated, the total dose of radiation and the treatment schedule. Tell your healthcare team if you have side effects that you think are from radiation therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

These are common side effects of radiation therapy for pancreatic cancer:

• fatigue
• skin problems, such as redness, itching and dryness, at the site where radiation was given •
• nausea and vomiting
• loss of appetite
• diarrhea
• weight loss

Find out more about radiation therapy and side effects of radiation therapy. To make the decisions that are right for you, ask your healthcare team questions about radiation therapy.