If you read their example, the pilot in question incurred a 1-in-320 increase in risk of fatal cancer. That's a 0.3% increase.

But you have to remember that 24% of americans will die of cancer anyway...so you add 0.3% to that and you get a 24.3% chance of fatal cancer.

You can reduce your non-occupational risk (the 24%) by various healthy- living techniques (diet, exercise, avoid chemicals, etc). I take vitamin E when flying to help with the free radicals.