Freaky, my father had the same thing, but it was a heart attack and a Quintuple (beat ya) heart bypass... No cancer that I know of...
He changed his diet for like a month, then figured he had all new piping so why bother? He could do another 40 years of damage to it...
I said that's a stupid way to think...
Anyway, glad your dad is ok... My dad doesn't live with me, but I made a point to spend plenty of time with him after this...
'People never get the flowers while they can still smell them.'