Precision delivery of radiation is often used in treating unresectable, invasive or malignant tumors of the brain & skull base.
While many intracranial tumors can be completely removed with surgery, others require additional treatments including chemotherapy, immuno-therapy and/or radiotherapy. Precision delivery of radiation with either Stereotactic Radiosurgery (SRS) or Stereotactic Radiotherapy (SRT) is commonly used for many such tumors to halt tumor growth.
Determining whether SRS or SRT are appropriate and safe for a given patient depends on several factors, most importantly the tumor type, its precise location relative to key brain structures, its growth rate and what prior treatments have been given.
Our comprehensive team approach which includes specialists in radiation oncology, neurosurgery, neuro-oncology and medical oncology allows for a personalized treatment for each patient.
Stereotactic Radiosurgery SRS is a single dose or up to 5 doses of highly focused radiation delivered to a tumor or vascular malformation. Radiosurgery is frequently used to treat brain, pituitary and skull base tumors that are not amenable to complete surgical removal or in patients with smaller metastatic brain tumors.
Key requirements for use of SRS is a tumor target that is at least 3 mm away from the optic nerves or chiasm or critical brainstem structures. For tumors less than 3 mm away from the optic nerves or chiasm, use of SRT (described below) is typically recommended. Radiosurgery can be delivered by a linear accelerator such as our Varian Trilogy LINAC or Cyberknife or by Gamma Knife technology; the effectiveness of these different forms of radiosurgery in terms of stopping tumor growth appears to be relatively equal.
Tumor types often treated with SRS: metastatic brain tumors, residual meningiomas, pituitary adenomas, chordomas, schwannomas.
Stereotactic Radiotherapy (SRT) is delivery of multiple doses of focused radiation therapy (up to 30 daily doses typically given over a 6 week period) to treat a tumor or vascular malformation that is not amenable to a single high dose of radiation (radiosurgery).
SRT is used specifically for tumors that are less than 3 mm away from the optic nerves or optic chiasm or brainstem structures in order to avoid damage to these critical normal structures. This type of focused stereotactic radiation method allows delivery of a maximal tumor dose to the tumor while minimizing radiation to normal structures.
Tumor types often treated with SRT: residual meningiomas, pituitary adenomas, craniopharyngiomas, chordomas, schwannomas, sinonasal carcinomas.
Whole Brain Radiotherapy (WBRT) is delivery of multiple fractions of radiation to a large area of the brain given over several days or weeks. WBRT is used less frequently now that SRS and SRT are available.
However, there is still a role for WBRT in patients with multiple metastatic brain tumors (typically more than 10) and in patients with other extensive malignant brain tumors such as leptomeningeal carcinomatosis.
Tumor types that may require WBRT: leptomeningeal carcinomatosis, multiple brain metastases (over 10), metastatic small cell lung carcinoma.