Brain tumors, malignant

Brain tumors, malignant

With an incidence of 4.5 per 100,000 patients, malignant brain tumors (gliomas, meningiomas, and schwannomas) are common (slightly more so in men than in women).

Tumors may occur at any age. In adults, incidence is generally highest between ages 40 and 60. The most common tumor types in adults are gliomas and meningiomas; these tumors are usually supratentorial (above the covering of the cerebellum).

In children, incidence is generally highest before age 1 and then again between ages 2 and 12. The most common tumors in children are astrocytomas, medulloblastomas, ependymomas, and brain stem gliomas. In children, brain tumors are one of the most common causes of death from cancer.


Some tumors are congenital, whereas others are hereditary. The cause of most brain tumors is unknown.

Signs and symptoms

Brain tumors cause central nervous system changes by invading and destroying tissues and by secondary effect—mainly compression of the brain, cranial nerves, and cerebral vessels; cerebral edema; and increased intracranial pressure (ICP). Generally, signs and symptoms result from increased ICP; these vary with the type of tumor, its location, and the degree of invasion. The onset of signs and symptoms is usually insidious, and brain tumors are commonly misdiagnosed. (See Clinical features of malignant brain tumors, pages 116 to 118.)


In many cases, a definitive diagnosis follows a tissue biopsy performed by stereotactic surgery. In this procedure, a head ring is affixed to the skull, and an excisional device is guided to the lesion by a computed tomography (CT) scan or magnetic resonance imaging (MRI).

Other diagnostic tools include a patient history, a neurologic assessment, skull X-rays, a brain scan, a CT scan, MRI, and cerebral angiography. Lumbar puncture shows increased pressure and protein levels, decreased glucose levels and, occasionally, tumor cells in cerebrospinal fluid (CSF).


Remedial approaches include removing a resectable tumor; reducing a nonresectable tumor; relieving cerebral edema, increased ICP, and other signs and symptoms; and preventing further neurologic damage.

The mode of therapy depends on the tumor’s histologic type, radiosensitivity,

and location and may include surgery, radiation, chemotherapy, or decompression of increased ICP with a diuretic, corticosteroid or, possibly, ventriculoatrial or ventriculoperitoneal shunting of CSF.

  • Gliomas. Treatment usually requires resection by craniotomy, followed by radiation therapy and chemotherapy. The combination of nitrosoureas (carmustine [BCNU], lomustine [CCNU], or procarbazine) and postoperative radiation is more effective than radiation alone.

  • Astrocytomas. Surgical resection of low-grade cystic cerebellar astrocytomas brings long-term survival. Treatment of other astrocytomas includes repeated surgery, radiation therapy, and shunting of fluid from obstructed CSF pathways. Some astrocytomas are
    highly radiosensitive, but others are radioresistant.

  • Oligodendrogliomas and ependymomas. Treatment includes resection and radiation therapy.

  • Medulloblastomas. Treatment involves resection and, possibly, intrathecal infusion of methotrexate or another antineoplastic.

  • Meningiomas. Treatment requires resection, including dura mater and bone (operative mortality may reach 10% because of large tumor size).

  • Schwannomas. Microsurgical technique allows complete resection of the tumor and preservation of facial nerves. Although schwannomas are moderately radioresistant, postoperative radiation therapy is necessary.