What is radiation therapy?

Radiation therapy is a treatment that uses strong rays of energy or particles to kill cancer cells. A machine directs the rays to the area of cancer. Radiation therapy is also called radiotherapy. Its goal is to kill or shrink cancer cells. If you have gallbladder cancer, radiation therapy may be part of your treatment.

When radiation therapy may be used

Radiation may be used to try to kill any cancer cells that may have been left behind after having a surgical procedure. This postoperative radiation therapy helps reduce the chances of the cancer growing back in the surgical site.

If your team determines that surgery cannot be done or really would not help, then radiation may be your main treatment. Or it may be combined with chemotherapy (chemo). This is most often done when the tumor has grown and may have spread to tissues near the gallbladder. If the cancer has spread to other parts of the body (metastasized), radiation can also be used. But it may be directed at other sites as well as the gallbladder area.

Sometimes the cancer has spread and cannot be completely cured. In certain cases, radiation can be used to reduce symptoms such as pain. This is called palliative radiation. For instance, it can help shrink a tumor that's pressing on nerves, the bile duct, or blood vessels. Or it may be used to keep a tube (stent) from closing off.

How radiation therapy is delivered

There are many different kinds of radiation. The most common type for treating gallbladder cancer is external beam radiation therapy (EBRT).

This type of radiation comes from a type of large X-ray machine outside your body. The machine may rotate over the area of treatment. The machine makes noise and moves around you. But it doesn't touch you. EBRT is a lot like getting an X-ray, but it takes longer.

For this treatment, you see a radiation oncologist. This is a healthcare provider who has extra training in the use of radiation to kill cancer cells. They decide how often you need radiation, how many sessions you may need, and the best dose to treat your cancer.               

The types of EBRT that may be used for gallbladder cancer are:

• 3-D conformal radiation therapy (3-D-CRT). With 3-D-CRT, radiation beams are aimed at the tumor from different angles. This makes it less likely to damage normal tissues.

• Intensity-modulated radiation therapy (IMRT). In IMRT, the radiation beams are also aimed from different directions. But the strength of the beams is also adjusted to keep the highest doses only on the tumor. This lets your healthcare team send an even higher dose to the cancer.

• Intraoperative radiation therapy. In some cases, radiation therapy is used during surgery. This way, it can directly target the cancer and prevent damage to nearby organs.

• Stereotactic body radiation therapy. This type of radiation delivers very strong focused doses to the cancer using a large X-ray machine or similar device. It is usually administered in 1 to 5 sessions. The high doses are limited to the cancerous target. This helps protect nearby tissues.

• Chemoradiation. Chemo is often given along with external beam radiation to help it work better.

Side effects of radiation therapy 

Radiation affects both normal cells and cancer cells. This means it can cause side effects. What the effects are depends on what part of your body is treated and what type of radiation you get. Some common side effects of EBRT include:

• Redness, blistering, and peeling of skin in the treatment area, like a sunburn

• Tiredness

• Upset stomach (nausea)

• Diarrhea

• Liver damage

Side effects tend to start a few weeks into treatment. Many get worse as treatment goes on. Then they slowly go away after treatment ends. Tell your healthcare team about side effects you have. There may be ways to help ease them.