Prognoses of primary brain tumors are determined by histologic type,
grade, postoperative size, and extent of the tumor and by the patient's
age, the performance status, and the duration of symptoms.[1,2]
Some primary brain tumors are curable by surgery alone, and some are
curable by surgery and radiation therapy; the remainder require surgery,
radiation therapy, and chemotherapy. Tumors that require all 3 modalities
are infrequently curable.
Metastases to the brain from a primary tumor that is outside the
central nervous system (CNS) are more common than primary tumors of the
brain. The most common primary tumors that metastasize to the brain are
lung, breast, melanoma, and kidney. Metastases to the brain are usually
multiple, but solitary metastases may also occur. Brain involvement can
occur with cancers of the nasopharyngeal region by direct extension along
the cranial nerves or through the foramina at the base of the skull.
Metastatic meningeal involvement can also occur, especially with leukemia,
lymphoma, small cell lung cancer, breast cancer, and some primary CNS
tumors (such as medulloblastoma and ependymal gliomas). A separate summary
containing information on primary CNS lymphoma is also available in PDQ.
A lesion in the brain should not be assumed to be a metastasis just
because a patient has had a previous cancer; such an assumption could
result in overlooking appropriate treatment of a curable tumor. Primary
brain tumors rarely spread to other areas of the body, but they can spread
to other parts of the brain and to the spinal axis.
References:
1. Levin VA, Leibel SA, Gutin PH: Neoplasms of the
central nervous system. In: DeVita VT Jr, Hellman S, Rosenberg SA, eds.:
Cancer: Principles and Practice of Oncology. Philadelphia, Pa: Lippincott-Raven
Publishers, 5th ed., 1997, pp 2022-2082.
2. Mahaley MS, Mettlin C, Natarajan N, et al.: National
survey of patterns of care for brain-tumor patients. Journal of
Neurosurgery 71(6): 826-836, 1989.
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