While it has been proven that Nitrates, Nitrites can cause cancer, moderation, as always, is the key.
This way of eating is hard enough without having to worry about every nitrate I intake a day. Especially when I think about what those carbs were doing to me...
If you want to get down to it, everthing from air freshener to bug spray can cause cancer.
I think it is really a matter of what you want to worry about. I personally do not worry about nitrate intake. However, I also don't eat 5 pounds of bacon a day.
Moderation.
Good luck,
-Chad