mrdavey1,
I drive a truck as well. I was told that smoking accounted for 75% of my cancer and chemical exposure from painting cars without a mask rounded out the final 25%. Doc never commented on the coffee or diet soda. I have read that truckers are more susceptible to bladder issues including possible links to cancer due to longer than normal periods without peeing. One thing my doctor stressed was drinking plenty of fluids and urinating often, even if it disrupted the truck schedule. You can imagine dispatch doesn't concur.
Let us know how you are doing. I hope you are getting on well.
Best wishes Mac (site moderator)