I am 100% confident that within the next two hundred years (baring some massive war, dark age, etc.) We will be able to use gene therapy to reduce cancer risk to negligible levels. We will probably even master the ability to program cells to do what we want... At which point all diseases where the body breaks down will likely be gone. That's not to say, we won't have issues regarding illness - just our bodies won't break down as quickly if at all.
