Chapter 3 - Overview of Epidemiology, Pathology, and Treatment of Metastatic Brain Tumors

Abstract

Metastatic brain tumors (MBT) are the most common complication of systemic cancer and affect between 20% and 40% of all adult cancer patients. Tumor cells usually reach the brain via hematogenous spread and often grow near the gray-white junction. Histologically, MBT resemble the parent tumor, with the potential for more undifferentiated features. Surgical resection is appropriate for solitary, accessible MBT in patients with high performance status and well-controlled systemic disease. In carefully selected patients with multifocal MBT, surgery may be appropriate for accessible, symptomatic, dominant lesions. Whole-brain external beam irradiation is the most common form of treatment for MBT, typically a total dose of 30Gy delivered in 10 daily fractions of 300cGy each. Radiosurgical boosting after whole-brain irradiation should also be considered for patients with one to four MBT. Chemotherapy can be of benefit in selected patients, especially those with MBT from cancers of the breast, lung (small cell and non-small cell), ovaries, and germ cell tumors. The most active agents include carboplatin, cisplatin, etoposide, cyclophosphamide, temozolomide, capecitabine, and topotecan. “Targeted” molecular agents are also under development that may have activity against MBT.