Stereotactic Radiotherapy

Specially trained cancer doctors called radiation oncologists are always working on ways to make radiation therapy treatments work better while at the same time preventing side effects. Doctors have had success in treating some cancers with a specialized type of radiation therapy called stereotactic radiotherapy (SRT).

SRT is a type of external beam radiation therapy that can be completed in one to five days rather than several weeks. SRT is best for very small tumors. Doctors use very specialized imaging equipment to pinpoint exactly where the cancer cells are. Doctors monitor the area of the cancer and other organs on a screen while treatment is taking place.

A customized holder may be used to keep the area to be treated perfectly still during treatment. Combining the specialized imaging and the custom holder allows doctors to give a high dose of radiation to the tumor in a short amount of time.

  • The advantage of SRT is it delivers the right amount of radiation to the cancer in a shorter amount of time than traditional treatments.
  • A Disadvantage of SRT is that it may not be able to be used effectively if the area where the cancer is located is too close to a sensitive normal structure, such as the bowel. That means smaller doses of radiation must be given to be safe.

Conditions Treated With SRT

SRT is usually called stereotactic radiosurgery (SRS) when referring to treating tumors in or near the brain or spinal cord. SRS is most commonly used to treat these conditions:

  • Cancers that spread to the brain (brain metastases).
  • Cancers that start in the brain (gliomas and other brain tumors).
  • Cancers that start on the surface of the brain, often near the base of the skull or ear canal (meningiomas or acoustic neuromas).
  • Cancer that has already received radiation and surgery is nor an option.
  • Very small tumors in the chest, abdomen or pelvis that cannot be removed surgically or treated with conventional radiation therapy.

SRT is usually called stereotactic body radiation therapy (SBRT) when referring to areas of the body other than the brain or spinal cord. SBRT is commonly used for these conditions:

  • Small lung cancers.
  • Cancers in the lung that started elsewhere (lung metastases).
  • Liver cancers that started outside the liver (liver metastases).

This list covers commonly treated conditions but does not include every possibility. SRT may be useful for other cancers not readily addressed with surgery or conventional radiation therapy. Patients with tumors that are small and few in number are the best candidates for SRT; not all patients can benefit from this type of treatment. Your radiation oncologist can tell you whether SRT is an options for your specific condition as new research continues to broaden the use of this technology.

Other Names for Stereotactic Treatment

Stereotactic radiotherapy is a highly specialized radiation therapy that goes by many different names depending upon the area of the body being treated and the type of equipment used. (This list is subject to change due to new technology and changes in the market place.)

Treatment names:

  • Stereotactic body radiotherapy (SBRT)
  • Stereotactic radiosurgery (SRS)
  • Stereotactic brain radiosurgery
  • Staged radiosurgery
  • Stereotactic radiation therapy (SRT)
  • Hypofractionated radiation therapy
  • Shaped beam surgery
  • TomoTherapy
  • Gamma Knife
  • CyberKnife

Brand names:

  • Accuray CyberKnife
  • Elekta Leksell Gamma Knife
  • Synergy, Axesse
  • Siemens Primatom
  • TomoTherapy Hi-Art
  • Varian/BrainLAB NovalisTx
  • Varian Trilogy

How Are These Treatments Alike?

All these devices are able to:

  • Use multiple narrow radiation beams.
  • Target small, well-defined areas with precision.
  • Use immobilization devices or techniques that monitor any movement during treatment.
  • Give high doses of radiation safely and accurately over a few treatments (usually one to five total treatments).

How Are These Treatments Different?

  • Different capabilities: Some stereotactic systems can treat only tumors in the head, others in the head and neck, and others anywhere in the body.
  • Different schedules: Some stereotactic treatments may be best given in a single session, others may be given in a few treatments over several days.
  • Different ways to achieve accuracy: Different systems use different ways to keep patients in the same position. Some use customized holders that keep the patient in the same position, others have the machine track any movement of the patient.

Who Is Qualified to Provide Radiation Therapy?

Radiation oncologists are physicians who are highly trained, board certified and licensed doctors who use radiation therapy in its various forms to care for patients with cancer. They are assisted by other members of the treatment team, including neurosurgeons, radiation therapists, radiation oncology nurses, medical physicists, dosimetrists, social workers and nutritionists. Radiation oncologists oversee the care of each person undergoing radiation treatment.

Where Should I Be Treated?

Modern radiation therapy facilities are widely available across the country. Not all of them offer every type of treatments. You should choose a center that offers the most appropriate treatments for your particular type of cancer. Possibilities include:

  • Academic medical centers located at major universities across the country.
  • Community hospital cancer centers.
  • Freestanding radiation therapy or cancer centers.

The suitability of a given treatment center will depend on the specific treatment you require, the technical capabilities of the center, the experience of the radiation oncologist, the location and possible restrictions from your health insurance plan.

How Do I Choose the Best Treatment For Me?

Choosing between treatments is confusing, and sometimes there is no simple answer. For many patients, there are several reasonable options. Factors to consider:

  • Have you had the opportunity to ask questions of your doctor and had them answered to your satisfactions?
  • Is reliable medical evidence available supporting the use of this system for a specific cancer available? (This evidence may be hard to find for some new technologies.)
  • What are the side effects?
  • Do you feel comfortable with the radiation oncologist?
  • Is travel required to get to the treatment?
  • Is it covered by insurance?

Things You Should Know

  • Question heavily advertised treatments that are not backed by scientific evidence.
  • Your physician should always discuss all of the appropriate, medically approved treatments related to your cancer. Be concerned if your doctor refuses to talk about other treatments.
  • You can always seek a second opinion. No doctor should discourage you from getting one.