Risk factors for kidney cancer in New South Wales--I. Cigarette smoking

In a population-based case-control study of kidney cancer in New South Wales, data from structured interviews with 489 cases of renal cell cancer (RCC), 147 cases of renal pelvic cancer (CaRP) diagnosed in 1989 and 1990, and 523 controls from the electoral rolls confirmed an increased risk associated with cigarette smoking in both types of cancer. The risk among current smokers was consistently higher than among ex-smokers, and was nearly twice as great for CaRP than for RCC. Additional information provided by this study includes reduced risks following cessation of smoking within 12 years for CaRP, but only after 25 years for RCC. Starting to smoke before, rather than after, the age of 18 years is linked independently with almost twice the risk for CaRP, but does not affect the risk for RCC. No independent trend was found with number of cigarettes smoked per day.