Many workers are exposed to industrial chemicals...I would guess that collectively they probably have at least a slightly higher risk of health problems (possibly including cancer) compared to say office workers.

Airline pilots have some elevated risk too, skin cancer and certain other problems. People speculate (and I agree) that the skin cancer risk probably has nothing to do with flying, and everything to do with having time off and as a group being more active and outdoor oriented than the general population. I suspect our biggest occupational risks are circadian rhythm disruption and constant exposure to Jet A fumes and exhaust (and possibly other things like hydraulic fluid). Risk due to crashing is very, very low (for airline pilots).