Relation of analgesic use to renal cancer: population-based findings.

A population-based case-control study of renal cancer (495 cases of renal cell cancer, 74 cases of renal pelvis cancer, and 697 controls) was conducted in the Minneapolis-St. Paul 7-county metropolitan area. Information was obtained on a large number of variables, including the use of analgesic drugs. Long-term use (greater than 36 mo) of phenacetin-containing products was associated in both sexes with a twofold increased risk for renal cell cancer. Long-term use of phenacetin- and acetaminophen-containing products was associated with elevated risks of nearly threefold to eightfold for cancer of the renal pelvis. The separate effects of these analgesics could not be adequately assessed because most long-term users took both products.