Intrathecal (IT) Herceptin (Trastuzumab) for brain mets (Leptomeningeal Metastases)

[Rolepaul]

Intrathecal can be done through a lumbar puncture hole, but is more commonly done through an Ommaya reservoir. This is a small under the skin plastic bag (think mini IV bag) with a septum to add the medications and a tube that allows the solution to go through a hole drilled in the skull to the brain cavity. Past issues with irritation of the brain lining from the tube or medication are better understood and not as much a problem. The medications are then added through the skin with a needle the size of a vaccination, with little pain or risk of infection. The medication volume is offeset by first removing an equivalent amount of fluid from the reservoir, which than can be used to flush the solution in the line at the end of medication addition or sent to the lab for study of the CSF for blood cells, glucose (high is good), protein (low is good), or tumor markers (undetectable is great). This is on the side of the blood brain barrier that most testing cannot see. That is why it is such a great tool if brain or spine involvement occurs.