The problem is that the mechanism of damage that forms the scar tissue is not just immediate, but progressive. So most people do not have immediate occlusion of the vessels at the end of treatment, but they gradually develop them over years. Much like other collateral damages from radiation, and the list is long, it is progressive and gets worse with time. Other things that radiation does that are the same, and I will just use my own list to note a few, - Your ability to swallow initially gets better, but over time gets worse. The radiation damages nerves that control the muscular contractions in the back of your throat, and that control the peristalses waves that move the food down. Other nerve damage include the facial nerve that controls your ability to move certain facial muscles. I can't control the right side of my mouth, there is nothing mechanically wrong with the muscles, but the nerves that control them have become progressively degraded by the radiation treatments over time.

Again using my own situation I noticed no lightheadedness or other symptoms of carotid blockage in the first 5 years after treatment, though there was likely some small gradual insidious thickening of the walls during that time. After that it seemed to worsen much more rapidly. Clearly I am not an expert on this, but have had it explained to me by my cardiologist who consulted with several RO's to confirm his findings. Stents are somewhere in my future, but I am dragging my feet about it and dealing with the QOL issues until they get to a point where I no longer can do some of the things that are important in my life. Perhaps time will run out for me before I really have to have them done. Mack Trucks run wild and all other considerations factored in......