Brain Metastasis

An overview of brain metastasis with respect to the pathological, diagnostic, and therapeutic aspects is presented. Management is almost always palliative, with cure being a rare exception. Evaluation of various therapeutic modalities—radiation, chemotherapy, or surgery—has been confounded by a lack of controlled, randomized studies whereby the relative benefit of the respective modalities can be assessed objectively. Despite these limitations, some progress is being made in the identification of those patients for whom therapy is likely to be of benefit. Apart from the use of steroids to control cerebral edema, radiotherapy is currently the most commonly employed therapeutic modality for cerebral metastasis. It is the treatment of choice for multiple intracranial metastases and it affords temporary improvement in neurological symptoms in about 60% of patients. For solitary metastases, combined therapy—surgical excision followed by whole brain radiotherapy—has been shown to result in a better quality and longer duration of survival than either modality alone. Except for patients who are terminally ill, aggressive treatment seems warranted, inasmuch as therapeutic results have been improving steadily over the years. Neither chemotherapy nor immunotherapy has been shown to be of benefit in the management of cerebral metastasis. An exception is choriocarcinoma, which responds well to a combination of radiation therapy and chemotherapy. Although the prognosis for meningeal carcinomatosis is poor, improved survival may be achieved by a combination of chemotherapy and radiotherapy. These are recommended guidelines for surgical intervention, usually followed by radiotherapy: (a) In general, surgical excision is recommended only for patients with relatively superficial, solitary lesions. It is reasonable, however, to consider the excision of a metastatic lesion that is immediately life-threatening or incapacitating, even though one or more other metastatic brain lesions may be present. This may be extended to the removal of multiple metastatic brain tumors if they are surgically accessible. (b) The second consideration is whether the primary tumor can or has been treated or if the primary tumor will permit reasonably long survival. (c) There should not be metastases elsewhere in the body, although their presence should not categorically exclude the patient as a surgical candidate. (d) The patient's general condition should be satisfactory. (e) Operation is recommended if the diagnosis of the intracranial lesion is uncertain. (f) A shunt should be considered for treatment of hydrocephalus secondary to obstruction of the cerebrospinal fluid pathway by tumor or edema.