Not all that obvious. We actually do have statistics on how X-ray scans affect your cancer odds. Full-body scans and other intense X-rays can have a 1 in 1000 chance of killing you in a couple of decades; most doctors won't consider them unless the condition they're hoping to diagnose is more dangerous than that.
Unfortunately not. Folks have some odd beliefs about medicine and with this, it isn't unlikely that a certain percentage of folks get cancer from medical treatments. I imagine that number is less in the modern world than it was before I was born. We did use Xrays to check how shoes fit, after all.