Thinking about this in the car yesterday. What is the possibility that this happens within our lifetime?
Transforming a human into a cyborg can include brain implants or extracting a human mind and placing it in a robotic life-support system. Even replacing biological organs with robotic ones could increase life span (i.e., pace makers) and depending on the definition, many technological upgrades to the body, like genetic modifications or the addition of nanobots would qualify an individual as a cyborg. Such modifications would make one impervious to aging and disease and theoretically immortal unless killed or destroyed.