Radiation therapy for bile duct cancer

Radiation therapy is treatment with high-energy rays or particles that destroy cancer cells. There are different kinds of radiation therapy.

External beam radiation therapy (EBRT)

This type of radiation therapy uses x-rays from a machine outside the patient's body to kill cancer cells. It is the most common form of radiation therapy for bile duct cancer. The treatment is much like getting an x-ray, but the radiation is more intense. The procedure itself is painless. Before your treatments start, the radiation team will take careful measurements to determine the correct angles for aiming the radiation beams and the proper dose of radiation. Each treatment lasts only a few minutes, but the setup time -- getting you into place for treatment -- usually takes longer. Most often, radiation treatments are given 5 days a week for several weeks.

Standard (conventional) EBRT is used much less often than in the past. With newer techniques, doctors can more accurately treat gallbladder cancers while reducing the radiation exposure to nearby healthy tissues. This may offer a better chance of increasing the success rate and reducing side effects.

Three-dimensional conformal radiation therapy (3D-CRT) uses special computers to precisely map the location of the tumor(s). Radiation beams are shaped and aimed at the tumor(s) from several directions, which makes it less likely to damage normal tissues. Most doctors now recommend using some form of 3D-CRT when it is available.

Intensity modulated radiation therapy (IMRT) is an advanced form of 3D therapy. It uses a computer-driven machine that actually moves around the patient as it delivers radiation. In addition to shaping the beams and aiming them at the bile duct from several angles, the intensity (strength) of the beams can be adjusted to minimize the dose reaching the most sensitive normal tissues. This lets doctors deliver an even higher dose to the cancer areas. This is available in many major hospitals and cancer centers.

Stereotactic body radiotherapy (SBRT) uses the techniques of 3D-CRT and IMRT, but gives the radiation over fewer sessions. A course of SBRT may take less than a week, while a course of radiation using these other techniques often takes place over 3 to 6 weeks.

Brachytherapy (internal radiation therapy)

This type of treatment uses small pellets of radioactive material placed next to or directly into the cancer. The radiation travels a very short distance, so it affects the cancer without causing much harm to nearby healthy body tissues. Brachytherapy is sometimes used in treating people with bile duct cancer by placing the pellets in a tube, which is inserted into the bile duct for a short time.

Uses of radiation therapy

Radiation therapy may be used in different ways to treat bile duct cancer:

After surgery for resectable cancers

This is known as adjuvant therapy. It is meant to kill any tiny deposits of cancer cells that remain after surgery (but are too small to see). Some doctors believe adjuvant radiation therapy is helpful, but more research is needed to confirm this.

As treatment before surgery for borderline resectable cancers

Some doctors may use radiation therapy before surgery for certain cancers that are thought to be resectable. This is done to try to shrink the cancer and make the operation easier and is known as neoadjuvant therapy. It's not clear how helpful this is.

As part of the main therapy for some advanced cancers

Radiation therapy can also be used as a main therapy for some patients whose cancer is not resectable but has not spread widely throughout the body. Most often it is given along with chemotherapy. While treatment in this case does not offer a cure, it may help patients to live longer.

As palliative therapy

Radiation therapy is often used to palliate (relieve) symptoms when a patient's cancer is too advanced to be cured. It may be used to relieve pain or other symptoms by shrinking tumors that are blocking passageways for blood or bile, or are pressing on nerves.

Radiation therapy is often given along with a chemotherapy drug called 5-fluorouracil (5-FU), which may make the radiation more effective. This is called chemoradiation. It may work better than giving radiation by itself, but often has more side effects.

Possible side effects of radiation therapy

Side effects of external radiation therapy might include:

• Skin changes (like a sunburn) where the radiation enters the body
• Nausea and vomiting
• Diarrhea
• Fatigue

Often these go away after treatment. When radiation is given with chemotherapy, the side effects are often worse.

For more general information about radiation therapy, please see our document, Understanding Radiation Therapy: A Guide for Patients and Families.