Abstract:Incidence rates of renal cell cancer, which accounts for 85% of kidney cancers, have been rising in the United States and in most European countries for several decades. Family history is associated with a two-to four-fold increase in risk, but the major forms of inherited predisposition together account for less than 4% of renal cell cancers. Cigarette smoking, obesity, and hypertension are the most consistently established risk factors. Analgesics have not been convincingly linked with renal cell cancer risk. A reduced risk of renal cell cancer among statin users has been hypothesized but has not been adequately studied. A possible protective effect of fruit and vegetable consumption is the only moderately consistently reported dietary fi nding, and, with the exception of a positive association with parity, evidence for a role of hormonal or reproductive factors in the etiology of renal cell cancer in humans is limited. A recent hypothesis that moderate levels of alcohol consumption may be protective for renal cell cancer is not strongly supported by epidemiologic results, which are inconsistent with respect to the categories of alcohol consumption and the amount of alcohol intake reportedly associated with decreased risk. For occupational factors, the weight of the evidence does not provide consistent support for the hypotheses that renal cell cancer may be caused by asbestos, gasoline, or trichloroethylene exposure. The established determinants of renal cell cancer, cigarette smoking, obesity, and hypertension, account for less than half of these cancers. Novel epidemiologic approaches, including evaluation of gene-environment interactions and epigenetic mechanisms of inherited and acquired increased risk, are needed to explain the increasing incidence of renal cell cancer. Keywords: renal cell cancer, epidemiology, risk factor, review
Descriptive epidemiologyKidney cancer is the ninth most common cancer in developed countries.1 Approximately 85% of kidney cancers are renal parenchyma (renal cell) cancers, while the remainder for the most part are urothelial cancers of the renal pelvis.2 Approximately 80% of renal cell cancers are clear cell adenocarcinomas, the remainder being papillary (∼15%), chromophobe (∼5%), and collecting duct carcinomas (Ͻ1%). Both renal cell and renal pelvis cancers are about twice as common among men as among women, [1][2][3] with the mean age at diagnosis in the early 60s for renal cell cancer and in the late 60s for renal pelvis cancer. For renal pelvis cancer, there is a strong tendency to develop multiple transitional epithelial tumors, particularly in the urinary bladder and ureter. 4 For the most part, renal pelvis cancer parallels bladder cancer in epidemiologic characteristics and risk factors and has been addressed by the authors elsewhere.