This measures resistance and sensitivity of their cancer to specific chemo agents and other alternative agents. This allows our doctors to change protocols immmediately rather than continue a course of treatment that is not effective. We start a patient on a course of chemo that is typical for their type of cancer but if the results of the test show (usually in 2-3 weeks) that the agents will not work or that another agent may work better, we have the ability to change in midstream. Most hospitals will follow a protocol for a specified amount of time.