Differential survival related to smoking among patients with renal cell carcinoma.

We examined the relation between tobacco smoking and survival among renal cell carcinoma cases, using information from a population-based cancer registry. Current smokers were at increased risk of death compared with non-smokers (hazard ratio (HR) 1.7, 95% CI = 1.2-2.5). The association was strongest within 6 months of diagnosis (HR 2.5, 95% CI = 1.5-4.3). Most of the association was explained by stage at diagnosis, with current smokers more likely (OR 2.2, 95% CI = 1.4-3.5) to have distant disease. Case-control studies may be biased if cases who do not participate owing to short survival have different smoking histories than participating cases.