Staged Stereotactic Radiosurgery (Staged SRS): What Does It Mean?

What Is Staged Stereotactic Radiosurgery (Staged SRS)?

Staged radiosurgery (staged stereotactic radiosurgery) is a treatment approach in which stereotactic radiosurgery (SRS) is not completed in a single session but is divided into multiple sessions separated by a certain interval. With Gamma Knife as well, staged treatment may be considered depending on the characteristics of the lesion.

Because the same lesion is treated in multiple sessions, this approach may look similar to fractionated treatment, but in general, “staged” and “fractionated” do not mean the same thing. In staged radiosurgery, the underlying idea is to leave a certain interval between treatments and to proceed with the next treatment while checking how the lesion has changed in the meantime. Fractionated stereotactic radiotherapy, on the other hand, includes approaches in which radiation is delivered in multiple sessions at relatively short intervals.

Is Gamma Knife Sometimes Divided Into Multiple Sessions for Large Brain Tumors?

Staged treatment may be considered, for example, for lesions that are too large to treat in a single session. However, which lesions it suits, how many sessions to divide it into, and how long the interval between treatments should be depend on factors such as the type, size, and location of the lesion, the surrounding tissue, and previous treatment. It cannot be applied to every large lesion.

In addition, while there are some clinical reports on staged Gamma Knife, the strength of the evidence varies by condition, and there is no single standard treatment method. For this reason, it cannot be generalized that “staged Gamma Knife treatment is always better for a large lesion.”

At our center, staged treatment may be considered and performed depending on the individual case. On the other hand, we do not currently present daily fractionated treatment as one of our main treatment options. Which treatment method is appropriate is determined by a specialist after reviewing MRI images and clinical information.

One reason staged radiosurgery may be considered is to treat the lesion while taking into account its size and the effects on important surrounding tissue. However, this does not mean that dividing treatment into stages will necessarily improve safety or treatment outcomes. Depending on the lesion, surgery, a different type of radiation therapy, medication, or another treatment may be more appropriate.

The medical literature includes reports of two-stage Gamma Knife treatment for large brain metastases and other lesions, but study methods and patient backgrounds vary, and no single approach has been established regarding who is a candidate or what the specific treatment schedule should be. This page is intended to help you understand the term. The number of sessions, intervals, and doses for each individual are determined through a treatment plan made by a specialist.