Radiation Treatment for Pancreatic Cancer

Radiation therapy (or radiotherapy) uses high-powered energy beams to kill cancer cells or prevent them from dividing. The beams can come from X-rays or other sources of radiation, such as protons or gamma rays.

Radiation therapy works by damaging the genetic material (DNA) in cancer cells located within the area where therapy is given. Subsequently, cancer cells with DNA that is beyond repair will stop dividing and die. Cells in the treated area will start to die in the days or weeks after treatment begins and continue to die for weeks or months after treatment ends.

While cancer cells can easily be eliminated by radioactive rays, healthy cells are more resistant to radiation. Normal cells are able to repair the damage caused by radiation at a much faster rate than cancer cells. This means that radiation therapy can destroy tumors and slow cancer growth while limiting damage to surrounding healthy tissue.

Radiation therapy can be given on its own or with chemotherapy (known as chemoradiation). Certain chemotherapy drugs, such as 5-fluorouracil, capecitabine, and gemcitabine, can make cancer cells more sensitive to radiation. Combining these two treatment modalities can accelerate the resulting DNA damage to pancreatic cancer cells and enhance the effectiveness of treatment.

Radiation therapy can be used to treat both resectable and unresectable pancreatic tumors.

Resectable pancreatic cancer

Radiation therapy or chemoradiation can be used in the following cases of resectable pancreatic cancer:

• Before surgery (known as neoadjuvant treatment), to shrink tumors that are too large for surgery at the time of diagnosis, thereby improving the chances of complete cancer removal with negative margins.
• After surgery (known as adjuvant treatment), to kill any residual cancer cells that were not visible during the operation and subsequently left behind, thereby lowering the chances of the cancer coming back in the surgical bed.

Unresectable (locally advanced) pancreatic cancer

For locally advanced cancers that cannot be removed with surgery, (chemo)radiation may be used, often following a period of chemotherapy, to help control tumor growth and relieve or prevent symptoms such as pain, bleeding, or bowel obstruction.

Metastatic pancreatic cancer

In select patients with metastatic disease, radiation may be used to treat the primary pancreatic tumor and even limited sites of metastatic disease (such as in the liver) to help control the disease and/or palliate symptoms.

The type of radiation therapy typically used in pancreatic cancer treatment is known as external beam radiation therapy (EBRT), which involves high doses of energy beams emitted from an external machine called a linear accelerator (LINAC).

External beam radiation therapy (EBRT)

Similar to the process of undergoing an X-ray, you will lie on a treatment table. The LINAC emits radiation directed towards the abdomen, where the pancreas is. Each treatment session lasts 10 to 30 minutes. While treatment itself only takes a few minutes, most of the session is spent getting you into the correct position on the table.

EBRT is usually administered five days a week over the course of several weeks. Your doctors will determine the number of sessions you need based on the type and stage of your cancer, as well as other health considerations.

Stereotactic body radiation therapy (SBRT)

An increasingly used technique in pancreatic cancer treatment is stereotactic body radiation therapy (SBRT). This specialized form of EBRT delivers very focused beams of high-dose radiation that are precisely and simultaneously aimed at the tumor from multiple different angles.

In SBRT, you will be put in a specially designed body frame, and a mold of your body near the tumor will be made. This maintains your position for each treatment session and ensures that the radiation is aimed at the exact same place each time. Doing so accounts for any movement of the tumor, as the pancreas moves when you breathe.

Compared to conventional EBRT, SBRT delivers higher doses of radiation per treatment session in fewer sessions. It is typically administered over five or fewer sessions, spanning one to two weeks. It also targets tumors more selectively, as the center of the tumor receives a high dose of radiation, while individual beams traveling through nearby tissues are of a low dose. In this way, surrounding healthy tissues can be well-protected from radiation exposure, leading to fewer side effects.

SBRT should only be offered in high-volume cancer centers with experience using this approach. You must also be deemed healthy enough to withstand such high-intensity treatment. If you’d like to explore SBRT as a treatment option, please consult your doctor(s) and cancer care team.

Like other types of cancer treatment, radiation therapy comes with possible risks and side effects. Some of the more common side effects of radiation therapy include:

• Skin problems, such as redness and blistering, in the treated area(s)
• Nausea and vomiting
• Diarrhea
• Fatigue
• Appetite loss
• Weight loss
• Abdominal discomfort and, rarely, ulcer formation

These issues typically resolve in the weeks after treatment ends. Rest assured, your doctor(s) will guide you on managing them.

Radiotherapy can take a toll on your body, so it is important to take care of your mental and emotional health. You may find it helpful to seek support from friends and family, as well as resources provided by your care team. They can provide emotional support, assist with daily tasks and offer a listening ear when you need it most. If you have any questions regarding radiation therapy, please consult your doctors and cancer care team.