As you say Dootch - it's bad timing. An event that triggers a DNA mutation (Philadelphia chromosome / CML) coupled with a weakened immune system for other reasons. I would also add - bombardment. By this I mean the creation of so many cancer cells at one time (as from a radiation event whether bomb made or medical (i.e. cat scans)) that the body is unable to dismember them all because they developed a micro T-cell environment to save them - keep them growing.
In my own case, I am convinced my trigger were a series of cat scans I had a few years prior to CML diagnosis. I later learned the cat scan device was not properly calibrated and was emitting high dose radiation. As it is a normal cat scan emits 70 times the radiation of an x-ray. Think about that .... 70 times:
I had five of these taken (when none were needed ... it could have been avoided).
Cat scans are dangerous. I will never have one again. As it is I am dealing with the aftermath of this massive radiation bombardment. And low vitamin D to boot - no wonder I developed CML.