Differential survival related to smoking among patients with renal cell carcinoma

We examined the relation between tobacco smoking and survival among renal c ell carcinoma cases, using information from a population-based cancer regis try. Current smokers were at increased risk of death compared with non-smok ers (hazard ratio (HR) 1.7, 95% CI = 1.2-2.5). The association was stronges t within 6 months of diagnosis (HR 2.5, 95% CI = 1.5-4.3). Most of the asso ciation was explained by stage at diagnosis, with current smokers more like ly (OR 2.2, 95% CI = 1.4-3.5) to have distant disease. Case-control studies may be biased if cases who do nut participate swing to short survival have different smoking histories chan participating cases.