The case for radiosurgery.

Abstract

Brain metastases represent a significant health-care problem, with almost 200,000 patient in the Unite States annually suffering from symptomatic parenchymal lesions. Lung, breast, melanoma, renal, and gastrointestinal cancers contribute the majority of lesions that come to clinical attention. Although median survival once brain metastases are diagnosed is less than a year, timely therapy can restore neurological function and can often prevent further neurological complications of cancer for the duration of a patient's survival. Important prognostic features associated with improved survival include the absence of extracranial disease progression, young age, a high pretreatment neurological status, one to three versus more than three lesions, and a long interval from primary disease diagnosis to the development of brain metastases. The need to aggressively treat brain metastases effectively is becoming increasingly important, however, as advances in the treatment of systemic disease result in an increasing number of patients developing brain metastases in the setting of limited systemic disease. For many such patients, surgery provides the best therapy, but results are still not encouraging because even patients with the best prognostic indicators often die within 18 to 24 months. Until Superior treatment modalities are developed, the judicious use of available techniques for treatment of patients with limited systemic disease provides the best opportunities for palliation and extended survival. Perhaps the most significant development in the treatment of patients with brain metastases during the last decade is the increasing use of radiosurgery. For patients with a single lesion, local control and survival rates of radiosurgery compare well with those produced with surgical resection. Radiosurgery remains an important treatment modality and, when used promptly, can reverse neurological deficits, often for the remainder of a patients life. There is compelling evidence to suggest that aggressive local therapy (surgery or radiosurgery) for patients with a single brain metastasis produces superior survival and quality of life compared with treatment with whole brain radiotherapy alone. However, surgery should be restricted to the minority of patients for whom brain metastases represents the life-threatening site of their disease. For an asymptomatic or mildly symptomatic patient with a lesion smaller than 3 cm in diameter, radiosurgery is an excellent alternative to surgery. Although radiosurgery is a noninvasive procedure, the same selection criteria should be considered as for those patients undergoing surgical resection.