International Brain Tumour Awareness Week
Saturday, 24th October to Saturday, 31st October 2020
Convection Enhanced Delivery
Convection Enhanced Delivery (CED) is a relatively new technique for delivering chemotherapy drugs directly into brain (and other) tumours. It is of particular interest for high grade tumours that cannot be operated on due to their location, or cannot be removed completely.
During a single, image-guided surgical operation, an access port is fixed to the skull, and up to four very narrow catheters are implanted in the brain. Depending on the location and size of the tumour, several catheters may be surgically placed to reach the tumour from different angles. These then stay in the brain.
When chemotherapy is to be given, the access port is attached to a set of pumps, which then deliver the drug treatment, at a precise rate and dose, directly into the brain.
The chemotherapy is given at precisely controlled infusion rates so as to create a pressure gradient at the catheter tips. This positive pressure drives fluid out from the catheter tip into the brain.
Catheter design has recently been improved to incorporate a ‘recessed-step’, where there is a drop from a large to a small diameter proximal to the catheter tip, and less chance of the drugs flowing back up the side of the catheter (called reflux).
The physical and chemical properties of the CED-infused drug also need to be optimised to ensure good distribution within the tumour site. The ideal drug should be water-soluble, of neutral or anionic charge, and have low tissue affinity or binding, although water insoluble drugs may be delivered by CED when ‘packaged’ within a nanoparticle.
CED is particularly attractive when repeated treatments are required because drugs can be repeatedly administered to the same target volume on separate occasions without the need for further surgery.
Funding Neuro video on YouTube.