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We evaluated the role of Gamma Knife stereotactic radiosurgery in the multidisciplinary management of brain metastases ovarian and endometrial, prostate, thyroid, sarcoma, or unknown primary cancers. From a series of over 3,000 patients who had Gamma Knife radiosurgery for brain metastases we reviewed indications and outcomes in patients with less common cancer types. All tumor types responded favorably to radiosurgery. Patients with male and female genitourinary primaries tended to develop brain metastases late in their course and did worse. Patients with thyroid metastases appear to live much longer with a more indolent course. Radiosurgery is an effective and safe minimally invasive option for patients with brain metastases from these less common primary origins., (Copyright © 2012 S. Karger AG, Basel.)

Advances in central nervous system imaging have resulted in early detection of a greater number of intracanalicular vestibular schwannomas. Early detection of intracanalicular vestibular schwannomas raises the issue of whether or not treatment is required and, if so, whether radiosurgery is the most appropriate option. Available evidence indicates that a majority of intracanalicular lesions are observed to grow and most will be associated with progressive hearing loss or, less frequently, sudden persistent hearing loss. If the objective of treatment is to preserve serviceable binaural hearing, early intervention is advisable. Early intervention is advantageous only if serviceable hearing can be maintained in the majority of patients along with low perioperative morbidity. Radiosurgery seems to achieve these goals ideally. Radiosurgery is a minimally invasive management option for patients with intracanalicular tumors. Radiosurgery provides high rate of long-term hearing preservation with minimal morbidity.

Fractionated stereotactic radiotherapy is an attractive, low-morbidity alternative to surgical resection for managing cranial nerve schwannomas. So far, the outcomes reported from fractionated stereotactic radiotherapy seem roughly equivalent to contemporary radiosurgery series. However, a randomized, controlled clinical trial is needed to adequately compare these techniques.

Stereotactic radiosurgery involves the use of precisely directed closed skull single-session radiation to create a desired radiobiologic response within the intracranial target with minimal effects to surrounding structures or tissues. It provided a way for physicians to administer high single doses of radiation to intracranial targets in patients with relative safety. Rapid advances in imaging and computer technologies in the last decade have resulted in development of a variety of different radiosurgery techniques and their wider applications. The Gamma Knife-, proton beam- and LINAC-based radiosurgery devices represent the three main radiosurgery systems. Successful clinical experience with radiosurgery for a diversity of applications has led to a re-examination of radiobiological principles. For radiosurgical doses, the response of the tumor or target tissue and the adjacent normal tissue seems determined predominantly by the supporting vasculature.