Brain Metastasis

What is Brain Metastasis?

In Siddhartha Mukherjee’s “The Emperor of All Maladies: A Biography of Cancer”, metastasis is defined as “the spread of tumors from one site to another, causing outcroppings of the disease in distant sites, such as the brain, the bones, or the lungs”. Brain cancer (tumors that develop within the brain) accounts for only 2 percent of all cancers but brain metastases (i.e. primary tumors that spread to the brain from distant sites) are more common with an estimated 10-20 percent of cancer patients. The frequency of brain metastases in different regions of the brain, are: cerebellum (15%), cerebrum (80%), and brainstem (5%).

What are the Causes of Brain Metastasis?

Any primary tumor that can spread to the brain is termed as brain metastasis.

Primary tumors of the lung, breast, kidney, colon, genitourinary tract, gastrointestinal tract, and the skin (melanoma) metastasize to the brain. Melanoma has the highest likelihood (nearly 50%) to metastasize to the brain.

Most common sources of brain metastases: The most common sources of brain metastases are lung, melanoma, and breast cancers. The tumor cells travel to the brain through the venous system (Batson’s plexus) that passes out from the skull and the spinal column or through the extensions of the sinus or the arteries.