Stereotactic radiosurgery for large brain metastases

Surgical resection still remains the mainstay of treatments for large brain metastases if feasible. Recently, stereotactic radiosurgery (SRS) using low-dose, 11- to 12-Gy marginal prescription dose, was tried to document the benefit for patients with large brain metastases when it was used as a primary or salvage treatment. Many large brain metastases responded promptly and showed favorable outcome after SRS. More than half of the patients recovered from their neurological deficits within 1 month after SRS. However, not negligible portion of patients were suffered from the adverse radiation effects and the final outcome was not same as that of optimal sized tumors for SRS. The safety of the current dose scheme for large brain metastases should be reevaluated in the near future, considering the relatively high rate of radiation-related injuries observed. Even with modern technology, SRS alone may not have any benefit in tumor volume reduction and survival for brain metastases larger than 26 cm(3) (an approximate maximum diameter of 3.5 cm).