I know one case doesn't really count, since we're talking population statistics here, but my dad had allergies and also had both primary bladder cancer and some years later primary lung cancer. I think in his case both were caused by long-term smoking, which most likely over-rode any possible "benefit" of allergies. Interesting idea, nonetheless. I wonder if people with auto-immune disorders (e.g., arthritis, lupus, etc.) might not be studied to see their incidence of bladder and related cancers.
Ann
Small TA Grade 1, May-06; recur (2 tiny), same, June-08; TURBTs both times. BCG begun July-08, dosage to 1/3rd May-10, completed treatment December-11. All clear since 2008.