I worked on Mesothelioma campaigns for a while. CPC averaged $100-150/click. It's literally AdWords most expensive CPC....but a Mesothelioma Lead is worth $10,000 and a settled case is worth $500,000. That's why Mesothelioma clicks are so expensive.
Keep an eye on AdCenter clicks...AdCenter causes many more headaches that AdWords.
Look at your search query reports..if you see anything outside of the norm, ask for a refund..and then add that term as a negative keyword. Its usually only broad match that will cause issues...if you don't use broad match, you shouldn't have many problems. Once again AdCenter will match up 'related' keywords that are not really related....AdWords is much more accurate for broad match keywords.
look at geo ... do you capture ip address on leads or server logs? look for IPs outside your targeted geo. If you find them, ask for a refund
If you find any issues, request that AdCenter or AdWords audit your account...I automatically did this every month with AdCenter ..and usually received 10-15% refund every month...and I didn't have to spend lot of time investigating things ...AdCenter did the work. Do you have a dedicated rep? this is what they are for.