Spinal tumors are sometimes treated with chemotherapy, which kills tumor cells directly, or with targeted therapies — drugs that prevent cancer cells from multiplying by zeroing in on specific molecules that help them grow.
Delivering chemotherapy to the spinal cord and central nervous system (CNS) can be challenging. That’s because your body’s blood-brain barrier is designed to protect the central nervous system from potentially harmful chemicals, including chemotherapy, by either preventing drugs from entering the CNS through the bloodstream or by actively pumping out any compounds that do manage get across.
One way to overcome this problem is to deliver relatively high doses of these drugs intravenously to overwhelm the “outflow pumps” in the blood-brain barrier, allowing some chemotherapy to pass into the central nervous system. A second way is to deliver chemotherapy intrathecally (through an injection into the cerebrospinal fluid surrounding the spinal cord) or through an Ommaya reservoir placed in the skull by a neurosurgeon. The Ommaya reservoir is connected to the brain’s ventricles — cerebrospinal fluid-filled spaces in the center of the brain. Drugs such as methotrexate and cytarabine are examples of chemotherapies that can be given both intravenously in high doses and intrathecally.
Targeted therapies are used more commonly for metastatic spinal cancers — tumors that have spread to the spine or central nervous system from other parts of the body. These drugs are often used in patients with melanoma, renal cell carcinoma, lung cancer, breast cancer and other cancers that have specific types of mutations that can be detected through molecular testing of the tumor tissue. They include:
- The BRAF inhibitors Zelboraf® (vemurafenib) and Fefinlar® (dabrafenib) and the MEK inhibitor Mekinist® (trametinib), used for lung cancer and melanoma
- ALK inhibitors, used for lung cancer
- HER2 blockers, such as Herceptin® (trastuzumab), used for HER2-positive breast cancer. Trastuzumab has also been given intrathecally in some patients.
Some of these drugs are given intravenously, while others are in pill form. These targeted therapies have stabilized spinal cord tumors in some patients with these types of tumors, and in some cases, the tumors have even shrunk.
Checkpoint inhibitors are a specific type of targeted therapy that stimulate your immune system to attack tumor cells. These types of therapies include Opdivo® (nivolumab), Keytruda® (pembrolizumab) and Yervoy® (ipilimumab). Like other targeted therapies, in some cases these drugs have stabilized or even reduced the size of metastatic spinal cord tumors.